Resist composition and method for producing resist pattern

ABSTRACT

A resist composition having a resin having a structural unit represented by the formula (I), a resin being insoluble or poorly soluble in alkali aqueous solution, but becoming soluble in an alkali aqueous solution by the action of an acid and not including the structural unit represented by the formula (I), and an acid generator represented by the formula (II), 
     
       
         
         
             
             
         
       
         
         
           
             wherein R 1 , A 1 , A 13 , A 14 , X 12 , R II1 , R II2 , L II1 , Y II1 , R II3 , R II4 , R II5 , R II6 , R II7 , n, s and R II8  are defined in the specification.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Application No. 2011-157526filed on Jul. 19, 2011. The entire disclosures of Japanese ApplicationNo. 2011-157526 is incorporated hereinto by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a resist composition and a method forproducing a resist pattern.

2. Background Information

A resist composition which contains a resin having a polymer containingstructural units represented by the formula (u-A) and the formula (u-B),and a polymer containing structural units represented by the formula(u-B), the formula (u-C) and the formula (u-D), as well as an acidgenerator, is described in Patent document of JP-2010-197413A.

However, with the conventional resist composition containing the aboveresin, the critical dimension uniformity (CDU) of the obtained resistpattern may be not always satisfied with.

SUMMARY OF THE INVENTION

The present invention provides following inventions of <1> to <10>.

<1> A resist composition having

a resin having a structural unit represented by the formula (I),

a resin being insoluble or poorly soluble in alkali aqueous solution,but becoming soluble in an alkali aqueous solution by the action of anacid and not including the structural unit represented by the formula(I), and

an acid generator represented by the formula (II),

wherein R¹ represents a hydrogen atom or a methyl group;

A¹ represents a C₁ to C₆ alkanediyl group;

A¹³ represents a C₁ to C₁₈ divalent aliphatic hydrocarbon group thatoptionally has one or more halogen atoms;

X¹² represents *—CO—O— or *—O—CO—;

* represents a bond to A¹³;

A¹⁴ represents a C₁ to C₁₇ aliphatic hydrocarbon group that optionallyhas one or more halogen atoms;

wherein R^(II1) and R^(II2) independently represent a fluorine atom or aC₁ to C₆ perfluoroalkyl group;

L^(II1) represents a single bond, a C₁ to C₆ alkanediyl, a C₄ to C₈divalent alicyclic hydrocarbon group, —(CH₂)_(t)—CO—O—* or—(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—*, one or more —CH₂— contained in thealkanediyl, —(CH₂)_(t)—CO—O—* or —(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—* may bereplaced by —O—;

t represents an integer of 1 to 12;

u represents an integer of 0 to 12;

* represents a bond to Y^(II1);

Y^(II1) represents an optionally substituted C₃ to C₁₈ alicyclichydrocarbon group, and one or more —CH₂— contained in the alicyclichydrocarbon group may be replaced by —O—, —CO— or —SO₂—;

R^(II3), R^(II4), R^(II5), R^(II6) and R^(II7) independently represent ahydrogen atom, a hydroxy group, a C₁ to C₆ alkyl group, a C₁ to C₆alkoxy group, a C₂ to C₇ alkoxycarbonyl group or a C₂ to C₁₂ acyloxygroup,

one or more —CH₂— contained in sulfur-containing ring of cation may bereplaced by —O— or —CO—;

n represents an integer of 1 to 3;

s represents an integer of 0 to 3; and

R^(II8) in each occurrence independently represent a C₁ to C₆ alkylgroup.

<2> The resist composition according to <1>, which further comprises anacid generator represented by the formula (III);

wherein R^(III1) and R^(III2) independently represent a fluorine atom ora C₁ to C₆ perfluoroalkyl group;

L^(III1) represents a single bond or a C₁ to C₁₇ divalent saturatedhydrocarbon group, one or more hydrogen atom in the saturatedhydrocarbon group may be replaced by a fluorine atom or a hydroxy group,and one or more —CH₂— contained in the saturated hydrocarbon group maybe replaced by —O— or —CO—;

Y^(III1) represents an optionally substituted C₁ to C₁₈ alkyl group oran optionally substituted C₃ to C₁₈ alicyclic hydrocarbon group, and oneor more —CH₂— contained in the alkyl group and alicyclic hydrocarbongroup may be replaced by —O—, —CO— or —SO₂—; and

Z⁺ represents an organic cation.

<3> The resist composition according to <2>, wherein Z⁺ in the formula(III) is a triaryl sulfonium cation.

<4> The resist composition according to any one of <1> to <3>, whereinA¹ in the formula (I) is an ethylene group.

<5> The resist composition according to any one of <1> to <4>, whereinA¹³ in the formula (I) is a C₁ to C₆ perfluoro alkanediyl group.

<6> The resist composition according to any one of <1> to <5>, whereinX¹² in the formula (I) is *—CO—O—, * represents a bond to A¹³.

<7> The resist composition according to any one of <1> to <6>, whereinA¹⁴ in the formula (I) is a cyclopropylmethyl, cyclopentyl, cyclohexyl,norbornyl or adamantyl group.

<8> The resist composition according to any one of <1> to <7>, whereinL^(II1) in the formula (II) is a bond or methylene group.

<9> The resist composition according to any one of <1> to <8>, whichfurther comprises a solvent.

<10> A method for producing a resist pattern comprising steps of;

(1) applying the resist composition of any one of <1> to <9> onto asubstrate;

(2) drying the applied composition to form a composition layer;

(3) exposing the composition layer;

(4) heating the exposed composition layer, and

(5) developing the heated composition layer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the chemical structure formulas of the present specification, unlessotherwise specified, the suitable choice of carbon number made for theexemplified substituent groups are applicable in all of the chemicalstructure formulas that have those same substituent groups. Unlessotherwise specified, these can include any of straight-chain, branchedchain, cyclic structure and a combination thereof. When there is astereoisomeric form, all stereoisomeric forms included.

“(Meth)acrylic monomer” means at least one monomer having a structure of“CH₂═CH—CO—” or “CH₂═C(CH₃)—CO—”, as well as “(meth)acrylate” and“(meth)acrylic acid” mean “at least one acrylate or methacrylate” and“at least one acrylic acid or methacrylic acid,” respectively.

<Resist Composition>

The resist composition of the present invention contains;

a resin (hereinafter is sometimes referred to as “resin (A)”), and

an acid generator represented by the formula (II) (hereinafter issometimes referred to as “acid generator (II)”).

Also, present resist composition preferably contains an acid generatorrepresented by the formula (III) (hereinafter is sometimes referred toas “acid generator (III)”).

Further, the present resist composition preferably contains a solvent(hereinafter is sometimes referred to as “solvent (E)”) and/or anadditive such as a basic compound (hereinafter is sometimes referred toas “basic compound (C)”) which is known as a quencher in this technicalfield, as needed.

<Resin (A)>

The resin (A) includes;

a resin having a structural unit represented by the formula (I)(hereinafter is sometimes referred to as “resin (A1)”), and

a resin being insoluble or poorly soluble in alkali aqueous solution,but becoming soluble in an alkali aqueous solution by the action of anacid and not including the structural unit represented by the formula(I) (hereinafter is sometimes referred to as “resin (A2)”).

Also, the resin (A) may contain a structural unit other than the resin(A1) and resin (A2).

<Resin (A1)>

The resin (A1) has a structural unit represented by the formula (I)(hereinafter is sometimes referred to as “structural unit (I)”).

wherein R¹ represents a hydrogen atom or a methyl group;

A¹ represents a C₁ to C₆ alkanediyl group;

A¹³ represents a C₁ to C₁₈ divalent aliphatic hydrocarbon group thatoptionally has one or more halogen atoms;

X¹² represents *—CO—O— or *—O—CO—;

* represents a bond to A¹³;

A¹⁴ represents a C₁ to C₁₇ aliphatic hydrocarbon group that optionallyhas one or more halogen atoms.

In the formula (I), examples of the alkanediyl group of A¹ include achain alkanediyl group such as methylene, ethylene, propane-1,3-diyl,propane-1,2-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl; abranched alkanediyl group such as 1-methylpropane-1,3-diyl,2-methylpropane-1,3-diyl, 2-methylpropane-1,2-diyl,1-methylbutane-1,4-diyl, 2-methylbutane-1,4-diyl groups.

Examples of the halogen atom of A¹³ include a fluorine, chlorine,bromine and iodine atoms. The fluorine atom is preferable.

The divalent aliphatic hydrocarbon group of A¹³ may be any of a chainand cyclic aliphatic hydrocarbon groups, and a combination of two ormore such groups. The aliphatic hydrocarbon group may include acarbon-carbon double bond, is preferably a saturated aliphatichydrocarbon group, and more preferably an alkanediyl group and adivalent alicyclic hydrocarbon group.

The aliphatic hydrocarbon group that optionally has one or more halogenatoms of A¹³ is preferably a saturated aliphatic hydrocarbon group thatoptionally has one or more fluorine atoms.

Examples of the chain divalent aliphatic hydrocarbon group thatoptionally has one or more halogen (preferably fluorine) atoms includemethylene, difluoromethylene, ethylene, perfluoroethylene, propanediyl,perfluoropropanediyl, butanediyl, perfluorobutanediyl, pentanediyl,perfluoropentanediyl, dichloromethylene and dibromomethylene groups.

The cyclic divalent aliphatic hydrocarbon group that optionally has oneor more halogen (preferably fluorine) atoms may be either monocyclic orpolycyclic hydrocarbon group. Examples thereof include a monocyclicaliphatic hydrocarbon group such as cyclohexanediyl,perfluorocyclohexanediyl and perchlorocyclohexanediyl; a polycyclicaliphatic hydrocarbon group such as adamantanediyl, norbornanediyl andperfluoro adamantanediyl groups.

The aliphatic hydrocarbon group of A¹⁴ may be any of a chain and cyclicaliphatic hydrocarbon groups, and a combination of two or more suchgroups. The aliphatic hydrocarbon group may include a carbon-carbondouble bond, is preferably a saturated aliphatic hydrocarbon group, andmore preferably an alkyl group and an alicyclic hydrocarbon group.

The aliphatic hydrocarbon group that optionally has one or more halogenatoms of A¹⁴ is preferably a saturated aliphatic hydrocarbon group thatoptionally has one or more fluorine atoms.

Examples of the chain aliphatic hydrocarbon group that optionally hasone or more halogen (preferably fluorine) atoms include trifluoromethyl,difluoromethyl, methyl, 1,1,1-trifluoroethyl, 1,1,2,2-tetrafluoroethyl,ethyl, perfluoroethyl, perfluoropropyl, 1,1,1,2,2-pentafluoropropyl,propyl, perfluorobutyl, 1,1,2,2,3,3,4,4-octafluorobutyl, butyl,perfluoropentyl, 1,1,1,2,2,3,3,4,4-nonafluoropentyl, pentyl, hexyl,perfluorohexyl, heptyl, perfluoroheptyl, octyl, perfluorooctyl,trichloromethyl, and tribromomethyl groups.

The cyclic aliphatic hydrocarbon group that optionally has one or morehalogen (preferably fluorine) atoms may be either monocyclic orpolycyclic hydrocarbon group. Examples thereof include the monocyclicaliphetic hydrocarbon group such as cyclopentyl, cyclohexyl,perfluorocyclohexyl and perchlorocyclohexyl; polycyclic aliphatichydrocarbon group such as adamantyl, norbornyl and perfluoro adamantylgroups.

Examples of the combination of the chain and cyclic aliphatichydrocarbon groups include cyclopropylmethyl, cyclopentylmethyl,cyclohexylmethyl, adamantylmethyl and perfluoro adamantylmethyl groups.

A¹ in the formula (I) is preferably a C₂ to C₄ alkanediyl group, andmore preferably an ethylene group.

The aliphatic hydrocarbon group of A¹³ is preferably a C₁ to C₆aliphatic hydrocarbon group, and more preferably a C₂ to C₃ aliphatichydrocarbon group.

The aliphatic hydrocarbon group of A¹⁴ is preferably a C₃ to C₁₂aliphatic hydrocarbon group, and more preferably a C₃ to C₁₀ aliphatichydrocarbon group. Among these, A¹⁴ is preferably a C₃ to C₁₂ aliphatichydrocarbon group which include an alicyclic hydrocarbon group, andstill more preferably cyclopropylmethyl, cyclopentyl, cyclohexyl,norbornyl and adamantyl groups.

Specific examples of the structural units (I) include as follows.

Also, examples of the structural units (I) include structural units inwhich a methyl group corresponding to IV in the structural unitsrepresented by the above is replaced by a hydrogen atom.

The structural unit (I) is derived from a compound represented by theformula (I′), hereinafter is sometimes referred to as “compound (I′)”.

wherein R¹, A¹, A¹³, X¹² and A¹⁴ have the same definition of the above.

The compound (I′) can be produced by a method below.

wherein R¹, A¹, A¹³, X¹² and A¹⁴ have the same definition of the above.

The compound (I′) can be obtained by reacting a compound represented bythe formula (Is-1) with a carboxylic acid represented by the formula(Is-2). This reaction is usually performed in presence of a solvent.Preferred examples of the solvent include tetrahydrofuran and toluene.This reaction may be coexistent with a known esterification catalyst,for example, an acid catalyst, carbodiimide catalyst.

As the compound represented by the formula (Is-1), a marketed product ora compound which is produced by a known method may be used. The knownmethod includes a method condensing (meth)acrylic acid or derivativesthereof, for example, (meth)acrylic chloride, with a suitable diol(HO-A¹-OH). The hydroxyethyl methacrylate can be used as a marketedproduct.

The carboxylic acid represented by the formula (Is-2) can be produced bya known method. Examples of the carboxylic acid represented by theformula (Is-2) include compounds below.

The resin (A1) may include a structural unit other than the structuralunit (I).

Examples of the structural unit other than the structural unit (I)include a structural unit derived from a monomer having an acid labilegroup described below (hereinafter is sometimes referred to as “acidlabile monomer (a1)”), a structural unit derived from a monomer nothaving an acid labile group described below (hereinafter is sometimesreferred to as “acid stable monomer”), a structural unit represented bythe formula (III-1) (hereinafter is sometimes referred to as “structuralunit (III-1)”) described below, a structural unit represented by theformula (III-2) (hereinafter is sometimes referred to as “structuralunit (III-2)”) described below, a structural unit derived from a knownmonomer in this field. Among these, the structural unit (III-1) and thestructural unit (III-2) are preferable.

wherein R¹¹ represents a hydrogen atom or a methyl group;

A¹¹ represents a C₁ to C₆ alkanediyl group;

R¹² represents a C₁ to C₁₀ hydrocarbon group having a fluorine atom.

wherein R²¹ represents a hydrogen atom or a methyl group;

ring W² represents a C₆ to C₁₀ hydrocarbon ring;

A²² represents —O—, *—CO—O— or *—O—CO—, * represents a bond to ring W²;

R²² represents a C₁ to C₆ alkyl group having a fluorine atom.

In the formula (III-1), examples of the alkanediyl group of A¹¹ includea chain alkanediyl group such as methylene, ethylene, propane-1,3-diyl,propane-1,2-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl; abranched alkanediyl group such as 1-methylpropane-1,3-diyl,2-methylpropane-1,3-diyl, 2-methylpropane-1,2-diyl,1-methylbutane-1,4-diyl and 2-methylbutane-1,4-diyl groups.

The hydrocarbon group having a fluorine atom of R¹² may be an alkylgroup having a fluorine atom and an alicyclic group having a fluorineatom.

Examples of the alkyl group include methyl, ethyl, n-propyl, iso-propyl,n-butyl, sec-butyl, tert-butyl, iso-butyl, n-pentyl, iso-pentyl,tert-pentyl, neo-pentyl and hexyl groups.

Examples of the alkyl group having a fluorine atom include a fluorinatedalkyl group such as, groups described below, difluoromethyl,trifluoromethyl, 1,1-difluoroethyl, 2,2-difluoroethyl,2,2,2-trifluoroethyl, perfluoroethyl, 1,1,2,2-tetrafluoropropyl,1,1,2,2,3,3-hexafluoropropyl, perfluoroethylmethyl,1-(trifluoromethyl)-1,2,2,2-tetrafluoroethyl, perfluoropropyl,1,1,2,2-tetrafluorobutyl, 1,1,2,2,3,3-hexafluorobutyl,1,1,2,2,3,3,4,4-octafluorobutyl, perfluorobutyl,1,1-bis(trifluoro)methyl-2,2,2-trifluoroethyl, 2-(perfluoropropyl)ethyl,1,1,2,2,3,3,4,4-octafluoropentyl, perfluoropentyl,1,1,2,2,3,3,4,4,5,5-decafluoropentyl,1,1-bis(trifluoromethyl)-2,2,3,3,3-pentafluoropropyl, perfluoropentyl,2-(perfluorobutyl)ethyl, 1,1,2,2,3,3,4,4,5,5-decafluorohexyl,1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexyl, perfluoropentylmethyl andperfluorohexyl groups.

The alicyclic hydrocarbon group is preferably a saturated ring of analiphatic hydrocarbon group in which a hydrogen atom is removed.Examples of the saturated ring of an aliphatic hydrocarbon group includegroups below.

Examples of the alicyclic hydrocarbon group having a fluorine atominclude a fluorinated cycloalkyl group such as perfluorocyclohexyl andperfluoroadamantyl groups.

The hydrocarbon ring of ring W² may be an alicyclic hydrocarbon ring,and preferably a saturated alicyclic hydrocarbon ring. Examples of thesaturated alicyclic hydrocarbon ring include adamantane and cyclohexanerings, and adamantane ring is preferable.

Examples of the structural unit (III-1) include structural units below.

Also, examples of the structural units (III-1) include structural unitsin which a methyl group corresponding to R¹¹ in the structural unitsrepresented by the above is replaced by a hydrogen atom.

Examples of the structural unit (III-2) include structural units below.

Also, examples of the structural units (III-2) include structural unitsin which a methyl group corresponding to R²¹ in the structural unitsrepresented by the above is replaced by a hydrogen atom.

The proportion of the structural unit (I) in the resin (A1) is generally5 to 100 mol %, preferably 10 to 100 mol %, with respect to the totalstructural units (100 mol %) constituting the resin (A1).

When the resin (A1) contains the structural unit (III-1) and/or thestructural unit (III-2), the total proportion thereof in the resin (A1)is generally 1 to 95 mol %, preferably 2 to 80 mol %, more preferably 5to 70 mol %, still more preferably 5 to 50 mol % and in particularpreferably 5 to 30 mol %, with respect to the total structural units(100 mol %) constituting the resin (A1).

The weight ratio of the structural unit (III-1): the structural unit(III-2) is preferably, for example, 0:100 to 100:0, more preferably 3:97to 97:3, still more preferably 50:50 to 95:5.

For achieving the proportion of the structural unit (I), the structuralunit (III-1) and/or the structural unit (III-2) in the resin (A1) withinthe above range, the amount of the compound (I′), a monomer giving thestructural unit (III-1) and/or a monomer giving the structural unit(III-2) to be used can be adjusted with respect to the total amount ofthe monomer to be used when the resin (A1) is produced (the same shallapply hereinafter for corresponding adjustment of the proportion).

The resin (A1) can be produced by a known polymerization method, forexample, radical polymerization method, using at least one of thecompound (I′), at least one of the monomer giving the structural unit(III-1) and/or at least one of the monomer giving the structural unit(III-2), as well as optionally at least one of the acid labile monomer(a1), least one of the acid stable monomer and/or at least one of aknown compound, described below.

The weight average molecular weight of the resin (A1) is preferably5,000 or more (more preferably 7,000 or more, and still more preferably10,000 or more), and 80,000 or less (more preferably 50,000 or less, andstill more preferably 30,000 or less).

The weight average molecular weight is a value determined by gelpermeation chromatography using polystyrene as the standard product. Thedetailed condition of this analysis is described in Examples.

<Resin (A2)>

The resin (A2) is a resin having properties which is insoluble or poorlysoluble in alkali aqueous solution, but becomes soluble in an alkaliaqueous solution by the action of an acid. Here “a resin becomingsoluble in an alkali aqueous solution by the action of an acid” means aresin that has an acid labile group and is insoluble or poorly solublein aqueous alkali solution before contact with the acid, and becomessoluble in aqueous alkali solution after contact with an acid.

Therefore, the resin (A2) is preferably a resin having at least onestructural unit derived from an acid labile monomer (a1).

Also, the resin (A2) may include a structural unit other than thestructural unit having the acid labile group as long as the resin (A2)has above properties and does not have the structural unit (I).

Examples of the structural unit other than the structural unit havingthe acid labile group include a structural unit derived from the acidstable monomer, the structural unit derived from a known monomer in thisfield, structural unit (III-1) and/or the structural unit (III-2)described above.

<Acid Labile Monomer (a1)>

The “acid labile group” means a group which has an elimination group andin which the elimination group is detached by contacting with an acidresulting in forming a hydrophilic group such as a hydroxy or carboxygroup. Examples of the acid labile group include a group represented bythe formula (1) and a group represented by the formula (2). Hereinaftera group represented by the formula (1) sometimes refers to as an “acidlabile group (1)”, and a group represented by the formula (2) sometimesrefers to as an “acid labile group (2)”.

wherein R^(a1) to R^(a3) independently represent a C₁ to C₈ alkyl groupor a C₃ to C₂₀ alicyclic hydrocarbon group, or R^(a1) and R^(a3) may bebonded together to form a C₂ to C₂₀ divalent hydrocarbon group, *represents a bond. In particular, the bond here represents a bondingsite (the similar shall apply hereinafter for “bond”).

wherein R^(a1′) and R^(a2′) independently represent a hydrogen atom or aC₁ to C₁₂ hydrocarbon group, R^(a3′) represents a C₁ to C₂₀ hydrocarbongroup, or R^(a2′) and R^(a3′) may be bonded together to form a divalentC₂ to C₂₀ hydrocarbon group, and one or more —CH₂— contained in thehydrocarbon group or the divalent hydrocarbon group may be replaced by—O— or —S—, * represents a bond.

Examples of the alkyl group of R^(a1) to R^(a3) include methyl, ethyl,propyl, butyl, pentyl and hexyl groups.

Examples of the alicyclic hydrocarbon group of R^(a1) to R^(a3) includemonocyclic hydrocarbon groups such as a cycloalkyl group, i.e.,cyclopentyl, cyclohexyl, methylcyclohexyl, dimethylcyclohexyl,cycloheptyl, cyclooctyl groups; and polycyclic hydrocarbon groups suchas decahydronaphtyl, adamantyl, norbornyl (i.e., bicyclo[2.2.1]heptyl),and methyl norbornyl groups as well as groups below.

The hydrogen atom contained in the alicyclic hydrocarbon group of R^(a1)to R^(a3) may be replaced an alkyl group. In this case, the carbonnumber of the alicyclic hydrocarbon group is comparable to the totalcarbon number of the alkyl group and the alicyclic hydrocarbon group.

The alicyclic hydrocarbon group of R^(a1) to R^(a3) preferably has 3 to16 carbon atoms, and more preferably has 4 to 16 carbon atoms.

When R^(a1) and R^(a2) is bonded together to form a C₂ to C₂₀ divalenthydrocarbon group, examples of the group-C(R^(a1))(R^(a2))(R^(a3))include groups below. The divalent hydrocarbon group preferably has 3 to12 carbon atoms. * represents a bond to —O—.

Specific examples of the acid labile group (1) include, for example,

1,1-dialkylalkoxycarbonyl group (a group in which R^(a1) to R^(a3) arealkyl groups, preferably tert-butoxycarbonyl group, in the formula (1)),

2-alkyladamantane-2-yloxycarbonyl group (a group in which R^(a1), R^(a2)and a carbon atom form adamantyl group, and R^(a3) is alkyl group, inthe formula (1)), and

1-(adamantine-1-yl)-1-alkylalkoxycarbonyl group (a group in which R^(a1)and R^(a2) are alkyl group, and R^(a3) is adamantyl group, in theformula (1)).

The hydrocarbon group of R^(a1′) to R^(a3′) includes any of an alkylgroup, an alicyclic hydrocarbon group and an aromatic hydrocarbon group.

Examples of the aromatic hydrocarbon group include an aryl group such asphenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl,p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl,phenanthryl, 2,6-diethylphenyl and 2-methyl-6-ethylphenyl groups.

Examples of the divalent hydrocarbon group which is formed by bondingwith R^(a2′) and R^(a3′) include a divalent aliphatic hydrocarbon group.

At least one of R^(a1′) and R^(a2′) is preferably a hydrogen atom.

Specific examples of the acid labile group (2) include a group below.

The acid labile monomer (a1) is preferably a monomer having an acidlabile group and a carbon-carbon double bond, and more preferably a(meth)acrylic monomer having the acid labile group.

Among the (meth)acrylic monomer having an acid labile group, it ispreferably a monomer having a C₅ to C₂₀ alicyclic hydrocarbon group.When a resin which can be obtained by polymerizing monomers having bulkystructure such as the alicyclic hydrocarbon group is used, the resistcomposition having excellent resolution tends to be obtained during theproduction of a resist pattern.

Examples of the (meth)acrylic monomer having the acid labile group (1)and a carbon-carbon double bond preferably include a monomer representedby the formula (a1-1) and a monomer represented by the formula (a1-2),below (hereinafter are sometimes referred to as a “monomer (a1-1)” and a“monomer (a1-2)”). These may be used as a single monomer or as acombination of two or more monomers.

wherein L^(a1) and L^(a2) independently represent *—O— or*—O—(CH₂)_(k1)—CO—O—, k1 represents an integer of 1 to 7, * represents abond to the carbonyl group;

R^(a4) and R^(a5) independently represent a hydrogen atom or a methylgroup;

R^(a6) and R^(a7) independently represent a C₁ to C₈ alkyl group or a C₃to C₁₀ alicyclic hydrocarbon group;

m1 represents an integer 0 to 14;

n1 represents an integer 0 to 10; and

n1′ represents an integer 0 to 3.

In the formula (a1-1) and the formula (a1-2), L^(a1) and L^(a2) arepreferably *—O— or *—O—(CH₂)_(k1′)—CO—O—, here k1′ represents an integerof 1 to 4 and more preferably 1, and more preferably *—O.

R^(a4) and R^(a5) are preferably a methyl group.

Examples of the alkyl group of R^(a6) and R^(a7) include methyl, ethyl,propyl, butyl, pentyl, hexyl and octyl groups. Among these, the alkylgroup of R^(a6) and R^(a7) is preferably a C₁ to C₆ alkyl group.

Examples of the alicyclic hydrocarbon group of R^(a6) and R^(a7) includemonocyclic hydrocarbon groups such as cyclopentyl, cyclohexyl,methylcyclohexyl, dimethylcyclohexyl, cycloheptyl, cyclooctyl groups;and polycyclic hydrocarbon groups such as decahydronaphtyl, adamantyl,norbornyl (i.e., bicyclo[2.2.1]heptyl), and methyl norbornyl groups aswell as groups above. Among these, the alicyclic hydrocarbon group ofR^(a6) and R^(a7) is preferably a C₃ to C₈ alicyclic hydrocarbon group,and more preferably a C₃ to C₆ alicyclic hydrocarbon group.

m1 is preferably an integer of 0 to 3, and more preferably 0 or 1.

n1 is preferably an integer of 0 to 3, and more preferably 0 or 1.

n1′ is preferably 0 or 1, and more preferably 1.

Examples of the monomer (a1-1) include monomers described in JP2010-204646A. Among these, the monomers are preferably monomersrepresented by the formula (a1-1-1) to the formula (a 1-1-8), and morepreferably monomers represented by the formula (a1-1-1) to the formula(a1-1-4) below.

Examples of the monomer (a1-2) include 1-ethyl-1-cyclopentane-1-yl(meth)acrylate, 1-ethyl-1-cyclohexane-1-yl (meth)acrylate,1-ethyl-1-cycloheptane-1-yl (meth)acrylate, 1-methyl-1-cyclopentane-1-yl(meth)acrylate and 1-isopropyl-1-cyclopentane-1-yl (meth)acrylate. Amongthese, the monomers are preferably monomers represented by the formula(a1-2-1) to the formula (a1-2-12), and more preferably monomersrepresented by the formula (a1-2-3), the formula (a1-2-4), the formula(a1-2-9) and the formula (a1-2-10), and still more preferably monomersrepresented by the formula (a1-2-3) and the formula (a1-2-9) below.

When the resin (A2) contains the structural unit (a1-1) and/or thestructural unit (a1-2), the total proportion thereof is generally 10 to95 mol %, preferably 15 to 90 mol %, more preferably 20 to 85 mol %,with respect to the total structural units (100 mol %) of the resin(A2).

Examples of a monomer having an acid-labile group (2) and acarbon-carbon double bond include a monomer represented by the formula(a1-5). Such monomer is sometimes hereinafter referred to as “monomer(a1-5)”. When the resin (A2) has the structural unit derived from themonomer (a1-5), a resist pattern tends to be obtained with less defects.

wherein R³¹ represents a hydrogen atom, a halogen atom or a C₁ to C₆alkyl group that optionally has a halogen atom;

Z¹ represents a single bond or *—O—(CH₂)_(k4)—CO-L⁴-, k4 represents aninteger of 1 to 4, * represents a bond to L¹;

L¹, L², L³ and L⁴ independently represent *—O— or *—S—.

s1 represents an integer of 1 to 3;

s1′ represents an integer of 0 to 3.

In the formula (a1-5), R³¹ is preferably a hydrogen atom, a methyl groupor trifluoromethyl group;

L¹ is preferably —O—;

L² and L³ are independently preferably *—O— or *—S—, and more preferably—O— for one and —S— for another;

s1 is preferably 1;

s1′ is preferably an integer of 0 to 2;

Z¹ is preferably a single bond or —CH₂—CO—O—.

Examples of the monomer (a1-5) include monomers below.

When the resin (A2) contains the structural unit derived from themonomer (a1-5), the proportion thereof is generally 1 to 50 mol %,preferably 3 to 45 mol %, and more preferably 5 to 40 mol %, withrespect to the total structural units (100 mol %) constituting the resin(A2).

<Acid Stable Monomer>

As the acid stable monomer, a monomer having a hydroxy group or alactone ring is preferable. When a resin containing the structural unitderived from a monomer having hydroxy group (hereinafter such acidstable monomer is sometimes referred to as “acid stable monomer (a2)”)or a acid stable monomer having a lactone ring (hereinafter such acidstable monomer is sometimes referred to as “acid stable monomer (a3)”)is used, the adhesiveness of resist pattern to a substrate andresolution of resist pattern tend to be improved.

<Acid Stable Monomer (a2)>

The acid stable monomer (a2), which has a hydroxy group, is preferablyselected depending on the kinds of an exposure light source at producingthe resist pattern.

When KrF excimer laser lithography (248 nm), or high-energy irradiationsuch as electron beam or EUV light is used for the resist composition,using the acid stable monomer having a phenolic hydroxy group such ashydroxystyrene as the acid stable monomer (a2) is preferable.

When ArF excimer laser lithography (193 nm), i.e., short wavelengthexcimer laser lithography is used, using the acid stable monomer havinga hydroxy adamantyl group represented by the formula (a2-1) as the acidstable monomer (a2) is preferable.

The acid stable monomer (a2) having the hydroxy group may be used as asingle monomer or as a combination of two or more monomers.

Examples of the acid stable monomer having hydroxy adamantyl include themonomer represented by the formula (a2-1).

wherein L^(a3) represents —O— or *—O—(CH₂)_(k2)—CO—O—;

k2 represents an integer of 1 to 7;

* represents a bind to —CO—;

R^(a14) represents a hydrogen atom or a methyl group;

R^(a15) and R^(a16) independently represent a hydrogen atom, a methylgroup or a hydroxy group;

o1 represents an integer of 0 to 10.

In the formula (a2-1), L^(a3) is preferably —O—, —O—(CH₂)_(f1)—CO—O—,here f1 represents an integer of 1 to 4, and more preferably —O—.

R^(a14) is preferably a methyl group.

R^(a15) is preferably a hydrogen atom.

R^(a16) is preferably a hydrogen atom or a hydroxy group.

o1 is preferably an integer of 0 to 3, and more preferably an integer of0 or 1.

Examples of the acid stable monomer (a2-1) include monomers described inJP 2010-204646A. Among these, the monomers are preferably monomersrepresented by the formula (a2-1-1) to the formula (a2-1-6), morepreferably monomers represented by the formula (a2-1-1) to the formula(a2-1-4), and still more preferably monomers represented by the formula(a2-1-1) and the formula (a2-1-3) below.

When the resin (A2) contains the acid stable structural unit derivedfrom the monomer represented by the formula (a2-1), the proportionthereof is generally 3 to 45 mol %, preferably 5 to 40 mol %, morepreferably 5 to 35 mol %, and still more preferably 5 to 30 mol %, withrespect to the total structural units (100 mol %) constituting the resin(A2).

<Acid Stable Monomer (a3)>

The lactone ring included in the acid stable monomer (a3) may be amonocyclic compound such as β-propiolactone ring, γ-butyrolactone,δ-valerolactone, or a condensed ring with monocyclic lactone ring andother ring. Among these, γ-butyrolactone and condensed ring withγ-butyrolactone and other ring are preferable.

Examples of the acid stable monomer (a3) having the lactone ring includemonomers represented by the formula (a3-1), the formula (a3-2) and theformula (a3-3). These monomers may be used as a single monomer or as acombination of two or more monomers.

wherein L^(a4) to L^(a6) independently represent —O— or*—O—(CH₂)_(k3)—CO—O—;

k3 represents an integer of 1 to 7, * represents a bind to —CO—;

R^(a18) to R^(a20) independently represent a hydrogen atom or a methylgroup;

R^(a21) in each occurrence represents a C₁ to C₄ alkyl group;

p1 represents an integer of 0 to 5;

R^(a22) to R^(a23) in each occurrence independently represent a carboxylgroup, cyano group, and a C₁ to C₄ alkyl group;

q1 and r1 independently represent an integer of 0 to 3.

In the formulae (a3-1) to (a3-3), L^(a4) to L^(a6) include the samegroup as described in L^(a3) above, and are independently preferably—O—, *—O—(CH₂)_(k3′)—CO—O—, here k3′ represents an integer of 1 to 4(preferably 1), and more preferably —O—;

R^(a18) to R^(a21) are independently preferably a methyl group.

R^(a22) and R^(a23) are independently preferably a carboxyl group, cyanogroup or methyl group;

p1 to r1 are independently preferably an integer of 0 to 2, and morepreferably an integer of 0 or 1.

Examples of the monomer (a3) include monomers described in JP2010-204646A. Among these, the monomers are preferably monomersrepresented by the formula (a3-1-1) to the formula (a3-1-4), the formula(a3-2-1) to the formula (a3-2-4), the formula (a3-3-1) to the formula(a3-3-4), more preferably monomers represented by the formula (a3-1-1)to the formula (a3-1-2), the formula (a3-2-3) to the formula (a3-2-4),and still more preferably monomers represented by the formula (a3-1-1)and the formula (a3-2-3) below.

When the resin (A2) contains the structural units derived from the acidstable monomer (a3) having the lactone ring, the total proportionthereof is preferably 5 to 70 mol %, more preferably 10 to 65 mol %,still more preferably 15 to 60 mol %, with respect to the totalstructural units (100 mol %) constituting the resin (A2).

When the resin (A2) is the copolymer of the acid labile monomer (a1) andthe acid stable monomer, the proportion of the structural unit derivedfrom the acid labile monomer (a1) is preferably 10 to 80 mol %, and morepreferably 20 to 60 mol %, with respect to the total structural units(100 mol %) constituting the resin (A2).

The resin (A2) preferably contains 15 mol % or more of the structuralunit derived from the monomer having an adamantyl group (in particular,the monomer having the acid labile group (a1-1)) with respect to thestructural units derived from the acid labile monomer (a1). As the moleratio of the structural unit derived from the monomer having anadamantyl group increases within this range, the dry etching resistanceof the resulting resist improves.

The resin (A2) preferably is a copolymer of the acid labile monomer (a1)and the acid stable monomer. In this copolymer, the acid labile monomer(a1) is preferably at least one of the acid labile monomer (a1-1) havingan adamantyl group and the acid labile monomer (a1-2) having acyclohexyl group, and more preferably is the acid labile monomer (a1-1).

The acid stable monomer is preferably the acid stable monomer (a2)having a hydroxy group and/or the acid stable monomer (a3) having alactone ring. The acid stable monomer (a2) is preferably the monomerhaving the hydroxyadamantyl group (a2-1). The acid stable monomer (a3)is preferably at least one of the monomer having the γ-butyrolactonering (a3-1) and the monomer having the condensed ring of theγ-butyrolactone ring and the norbornene ring (a3-2).

The resin (A2) can be produced by a known polymerization method, forexample, radical polymerization method, using at least one of the acidlabile monomer (a1) and/or at least one of the acid stable monomer (a2)having a hydroxy group and/or at least one of the acid stable monomer(a3) having a lactone ring and/or at least one of a known compound.

The weight average molecular weight of the resin (A2) is preferably2,500 or more (more preferably 3,000 or more, and still more preferably4,000 or more), and 50,000 or less (more preferably 30,000 or less, andstill more preferably 10,000 or less).

In the present resist composition, the weight ratio of the resins(A1)/(A2) is preferably, for example, 0.01/10 to 5/10, more preferably0.05/10 to 3/10, still more preferably 0.1/10 to 2/10, in particular,preferably 0.2/10 to 1/10.

<Resin Other than Resin (A1) and Resin (A2)>

The resist composition of the present invention may include a resinother than the resin (A1) and the resin (A2) described above. Such resinis a resin having at least one of the structural unit derived from theacid labile monomer (a1), at least one of the acid stable monomer, asdescribed above, and/or at least one of a known monomer in this field.

The proportion of the resin (A) can be adjusted with respect to thetotal solid proportion of the resist composition. For example, theresist composition of the present invention preferably contains 80weight % or more and 99 weight % or less of the resin (A), with respectto the total solid proportion of the resist composition.

In the specification, the term “solid proportion of the resistcomposition” means the entire proportion of all ingredients other thanthe solvent (E).

The proportion of the resin (A) and the solid proportion of the resistcomposition can be measured with a known analytical method such as, forexample, liquid chromatography and gas chromatography.

<Acid Generator (II)>

The acid generator (II) included in the resist composition of thepresent invention includes a salt represented by the formula (II);

wherein R^(II1) and R^(II2) independently represent a fluorine atom or aC₁ to C₆ perfluoroalkyl group;

L^(II1) represents a single bond, a C₁ to C₆ alkanediyl, a C₄ to C₈divalent alicyclic hydrocarbon group, —(CH₂)_(t)—CO—O—* or—(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—*, one or more —CH₂— contained in thealkanediyl, —(CH₂)_(t)—CO—O—* or —(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—* may bereplaced by —O—;

t represents an integer of 1 to 12;

u represents an integer of 0 to 12;

* represents a bond to Y^(II1);

Y^(II1) represents an optionally substituted C₃ to C₁₈ alicyclichydrocarbon group, and one or more —CH₂— contained in the alicyclichydrocarbon group may be replaced by —O—, —CO— or —SO₂—;

R^(II3), R^(II4), R^(II5), R^(II6) and R^(II7) independently represent ahydrogen atom, a hydroxy group, a C₁ to C₆ alkyl group, a C₁ to C₆alkoxy group, a C₂ to C₇ alkoxycarbonyl group or a C₂ to C₁₂ acyloxygroup,

one or more —CH₂— contained in sulfur-containing ring of cation may bereplaced by —O— or —CO—;

n represents an integer of 1 to 3;

s represents an integer of 0 to 3; and

R^(II8) in each occurrence independently represent a C₁ to C₆ alkylgroup.

In the formula (II), a moiety having a positive charge sometimes referto as an organic cation, and a moiety having a negative charge sometimesrefer to as a sulfonate anion.

Examples of the perfluoroalkyl group of R^(II1) and R^(II2) includetrifluoromethyl, perfluoroethyl, perfluoropropyl, perfluoro-isopropyl,perfluorobutyl, perfluoro-sec-butyl, perfluoro-tert-butyl,perfluoropentyl and perfluorohexyl groups.

Among these, R^(II1) and R^(II2) independently are preferablytrifluoromethyl or fluorine atom, and more preferably a fluorine atom.

The alkanediyl group of L^(II1) may be any of a linear chain alkanediylgroup and a branched chain alkanediyl group.

Specific examples of the linear chain alkanediyl group includemethylene, ethylene, propane-1,3-diyl, propane-1,2-diyl,butane-1,4-diyl, pentane-1,5-diyl and hexane-1,6-diyl groups.

Specific examples of the branched chain alkanediyl group include a groupin which a linear chain alkanediyl group has a side chain of an alkylgroup (especially a C₁ to C₄ alkyl group such as methyl, ethyl, propyl,isopropyl, butyl, sec-butyl, tert-butyl groups) such as butan-1,3-diyl,2-methylpuropane-1,3-diyl, 2-methylpuropane-1,2-diyl, pentan-1,4-diyland 2-methylbutane-1,4-diyl groups.

Examples of the alkanediyl in which one or more —CH₂-contained in thealkanediyl is replaced by —O— include —CH₂—O—, —CH₂—CH₂—O—,—CH₂—CH₂—CH₂—O— and —CH₂—CH₂—O—CH₂—, among these, —CH₂—CH₂—O— ispreferable.

Examples of divalent alicyclic hydrocarbon group of L^(II1) includecycloalkanediyl group such as cyclobutan-1,3-diyl,cyclopenthan-1,3-diyl, cyclohexan-1,2-diyl, 1-methylcyclohexan-1,2-diyl,cyclohexan-1,4-diyl, cyclooctan-1,2-diyl and cyclooctan-1,5-diyl groups.

Examples of —(CH₂)_(t)—CO—O—* of L^(II1) include —CH₂—CO—O—*,—(CH₂)₂CO—O—*, —(CH₂)₃—CO—O—*, —(CH₂)₄—CO—O—*, —(CH₂)₆—CO—O—* and—(CH₂)₈—CO—O—*, among these, —CH₂—CO—O—* and —(CH₂)₂—CO—O—* arepreferable.

Examples of —(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—* of L^(II1) include—CH₂—CO—O—CH₂—*, —CH₂—CO—O—CH₂—CH₂—*, —CH₂—CO—O—CH₂—(CH₂)₂—*,—CH₂—CO—O—CH₂—CH₂—O—* and —CH₂—CO—O—CH₂—CH₂—O—CH₂—*.

For L^(II1), a single bond or a C₁ to C₆ alkanediyl group are preferableand a single bond or a methylene group are more preferable.

Examples of the alicyclic hydrocarbon group of Yin include monocyclicand polycyclic cycloalkyl groups represented by the formula (Y1) to theformula (Y11). The cycloalkyl groups also include groups in which a C₁to C₁₂ alkyl group is bonded to the atom constituting the ring, forexample, groups represented by the formula (Y27) to the formula (Y29).The alicyclic hydrocarbon group is preferably a C₃ to C₁₂ cycloalkylgroup.

Examples of the substituent of Yin include a halogen atom (other thanfluorine atom), a hydroxy group, a C₁ to C₁₂ alkoxy group, a C₆ to C₁₈aromatic hydrocarbon group, a C₇ to C₂₁ aralkyl group, a C₂ to C₄ acylgroup, a glycidyloxy group or a —(CH₂)_(j2)—O—CO—R^(i1) group, whereinR^(i1) represents a C₁ to C₁₆ aliphatic hydrocarbon group, a C₃ to C₁₆alicyclic hydrocarbon group or a C₆ to C₁₈ aromatic hydrocarbon group,j2 represents an integer of 0 to 4. The aromatic hydrocarbon group andthe aralkyl group of the substituent may further have a substituent suchas a C₁ to C₈ alkyl group, a halogen atom or a hydroxy group.

Examples of the halogen atom include fluorine, chlorine, bromine andiodine atoms.

Examples of the alkoxyl group include methoxy, ethoxy, n-propoxy,isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentyloxy, n-hexyloxy,heptyloxy, octyloxy, 2-ethylhexylozy, nonyloxy, decyloxy, undecyloxy anddodecyloxy groups.

Examples of the aromatic hydrocarbon group include an aryl group such asphenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl,p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl,phenanthryl, 2,6-diethylphenyl and 2-methyl-6-ethylphenyl groups.

Examples of the aralkyl group include benzyl, phenethyl, phenylpropyl,naphthylmethyl and naphthylethyl groups.

Examples of the acyl group include acetyl, propionyl and butyryl groups.

Examples of the aliphatic hydrocarbon group of R^(i1) include methyl,ethyl, propyl, butyl, pentyl, hexyl, heptyl and octyl groups.

Examples of the alicyclic hydrocarbon group of R^(i1) include monocyclichydrocarbon groups, cycloalkyl group, such as cyclopentyl, cyclohexyl,methylcyclohexyl, dimethylcyclohexyl, cycloheptyl, cyclooctyl groups;and polycyclic hydrocarbon groups such as decahydronaphtyl, adamantyl,norbornyl (i.e., bicyclo[2.2.1]heptyl), and methyl norbornyl groups aswell as groups below.

Examples of the aromatic hydrocarbon group include the same examplesdescribed above.

Examples of the alicyclic hydrocarbon group of Y^(II1) in which one ormore —CH₂— is replaced by the —O—, —SO₂— or —CO— include

a cyclic ether group which is a group in which one or two —CH₂—contained in the alicyclic hydrocarbon group is replaced by the —O—;

a cyclic ketone group which is a group in which one or two —CH₂—contained in the alicyclic hydrocarbon group is replaced by the —CO—;

a sultone ring group which is a group in which an adjacent two —CH₂—contained in the alicyclic hydrocarbon group are replaced by the —O— and—SO₂—, respectively;

a lactone ring group which is a group in which an adjacent two —CH₂—contained in the alicyclic hydrocarbon group are replaced by the —O— and—CO—, respectively; and

groups represented by the formula (Y12) to the formula (Y26).

In the above formula, * represents a bond to L^(II1).

Among these, Y^(II1) is preferably any one of groups represented by theformula (Y1) to the formula (Y19) and the formula (Y27) to the formula(Y29), more preferably any one of groups represented by the formula(Y11), (Y14), (Y15), (Y19) and the formula (Y27) to the formula (Y29),and still more preferably group represented by the formula (Y11) and(Y14).

Examples of the alicyclic hydrocarbon group having a hydroxy groupinclude groups below.

Examples of the alicyclic hydrocarbon group having a C₆ to C₁₈ aromatichydrocarbon group include groups below.

Examples of the alicyclic hydrocarbon group having—(CH₂)_(j2)—O—CO—R^(i1) include groups below.

Y^(II1) is preferably an adamantyl group which is optionallysubstituted, for example, an oxo group and a hydroxy group, and morepreferably an adamantyl group, a hydroxyadamantyl group and anoxoadamantyl group.

The sulfonate anion is preferably an anions represented by the formula(b1-1-1) to the formula (b1-1-9) below. In the formula (b1-1-1) to theformula (b1-1-9), R^(II1), R^(II2) and L^(II1) represents the samemeaning as defined above. R^(b2) and R^(b3) independently represent a C₁to C₄ alkyl group (preferably methyl group).

The sulfonate anion in which Y^(II1) is a non-substituted alicyclichydrocarbon group and L^(II1) is a single bond or a C₁ to C₆ alkanediylgroup is preferable. Examples of thereof include sulfonate anions below.

Examples of the sulfonate anion in which Y^(II1) is an alicyclic grouphaving —(CH₂)_(j2)—O—CO—R^(i1) and L^(II1) is a single bond or a C₁ toC₆ alkanediyl group include sulfonate anions below.

Examples of the sulfonate anion in which Y^(II1) is an alicyclic grouphaving a hydroxy group and L^(II1) is a single bond or a C₁ to C₆alkanediyl group include sulfonate anions below.

Examples of the sulfonate anion in which Y^(II1) is an alicyclic grouphaving an aromatic hydrocarbon group or an aralkyl group and L^(II1) isa single bond or a C₁ to C₆ alkanediyl group include sulfonate anionsbelow.

Examples of the sulfonate anion in which Y^(II1) is a cyclic ether groupand L^(II1) is a single bond or a C₁ to C₆ alkanediyl group includesulfonate anions below.

Examples of the sulfonate anion in which Y^(II1) is a lactone ring groupand L^(II1) is a single bond or a C₁ to C₆ alkanediyl group includesulfonate anions below.

Examples of the sulfonate anion in which Y^(II1) is a cyclic ketonegroup and L^(II1) is a single bond or a C₁ to C₆ alkanediyl groupinclude sulfonate anions below.

Examples of the sulfonate anion in which Y^(II1) is a sultone ring groupand L^(II1) is a single bond or a C₁ to C₆ alkanediyl group includesulfonate anions below.

Examples of the sulfonate anion in which Y^(II1) is a non-substitutedalicyclic hydrocarbon group and Y^(II1) is —(CH₂)_(t)—CO—O—* or—(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—* include sulfonate anions below.

Examples of the sulfonate anion in which Y″ is an alicyclic group having—(CH₂)_(j2)—O—CO—R^(i1) and L^(II1) is —(CH₂)_(t)—CO—O—* or—(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—* include sulfonate anions below.

Examples of the sulfonate anion in which Y^(II1) is an alicyclic grouphaving a hydroxy group and L^(II1) is —(CH₂)_(t)—CO—O—* or—(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—* include a sulfonate anions below.

Examples of the sulfonate anion in which Y^(II1) is an alicyclic grouphaving a aromatic hydrocarbon group and L^(II1) is —(CH₂)_(t)—CO—O—* or—(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—* include a sulfonate anions below.

Examples of the sulfonate anion in which Y^(II1) is a cyclic ether groupand L^(II1) is —(CH₂)_(t)—CO—O—* or —(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—*include a sulfonate anions below.

Examples of the sulfonate anion in which Y^(II1) is a lactone ring groupand L^(II1) is —(CH₂)_(t)—CO—O—* or —(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—*include a sulfonate anions below.

Examples of the sulfonate anion in which Y^(II1) is a cyclic ketonegroup and L^(II1) is —(CH₂)_(t)—CO—O—* or—(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—* include a sulfonate anions below.

Examples of the sulfonate anion in which Y^(II1) is a sultone ring groupand L^(II1) is —(CH₂)_(t)—CO—O—* or —(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—*include a sulfonate anions below.

Examples of the sulfonate anion in which Y^(II1) is a non-substitutedalicyclic hydrocarbon group and L^(II1) is —(CH₂)_(t)—CO—O—* or—(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—* include a sulfonate anions below.

Among these, sulfonate anions as described below are preferable.

Examples of the alkyl group of R^(II3) to R^(II7) include methyl, ethyl,propyl and butyl groups.

Examples of the alkoxyl group include methoxy, ethoxy, propoxy,isopropoxy and butoxy groups.

Examples of the acyloxy group include acetyloxy and benzyloxy groups.

Examples of the alkyl group of R^(II8) include methyl, ethyl, propyl,butyl, pentyl and hexyl groups.

Examples of groups in which one or more —CH₂— contained insulfur-containing ring of cation is replaced by —O— or —CO— includebelow.

Examples of the organic cations include cations below.

Examples of the acid generator (II) include salts in combination asulfonate anion and an organic cation as described in the tables.

TABLE 1 Acid generator (II) Sulfonate anion Organic cation (II-1)(II-a-2) (II-c-7) (II-2) (II-a-2) (II-c-13) (II-3) (II-a-2) (II-c-20)(II-4) (II-a-3) (II-c-13) (II-5) (II-a-2) (II-c-10) (II-6) (II-a-2)(II-c-4) (II-7) (II-a-1) (II-c-1) (II-8) (II-a-2) (II-c-1) (II-9)(II-a-3) (II-c-1) (II-10) (II-a-4) (II-c-1) (II-11) (II-a-5) (II-c-1)(II-12) (II-a-6) (II-c-1) (II-13) (II-a-7) (II-c-1) (II-14) (II-a-1)(II-c-2) (II-15) (II-a-2) (II-c-2) (II-16) (II-a-3) (II-c-2) (II-17)(II-a-5) (II-c-2) (II-18) (II-a-7) (II-c-2) (II-19) (II-a-1) (II-c-3)(II-20) (II-a-2) (II-c-3) (II-21) (II-a-3) (II-c-3) (II-22) (II-a-5)(II-c-3) (II-23) (II-a-7) (II-c-3) (II-24) (II-a-1) (II-c-4) (II-25)(II-a-3) (II-c-4) (II-26) (II-a-4) (II-c-4) (II-27) (II-a-5) (II-c-4)(II-28) (II-a-6) (II-c-4) (II-29) (II-a-7) (II-c-4) (II-30) (II-a-1)(II-c-5) (II-31) (II-a-2) (II-c-5) (II-32) (II-a-3) (II-c-5) (II-33)(II-a-5) (II-c-5) (II-34) (II-a-7) (II-c-5) (II-35) (II-a-1) (II-c-6)(II-36) (II-a-2) (II-c-6) (II-37) (II-a-3) (II-c-6) (II-38) (II-a-5)(II-c-6) (II-39) (II-a-7) (II-c-6) (II-40) (II-a-1) (II-c-7) (II-41)(II-a-3) (II-c-7) (II-42) (II-a-4) (II-c-7) (II-43) (II-a-5) (II-c-7)(II-44) (II-a-6) (II-c-7) (II-45) (II-a-7) (II-c-7) (II-46) (II-a-1)(II-c-8) (II-47) (II-a-2) (II-c-8) (II-48) (II-a-3) (II-c-8) (II-49)(II-a-5) (II-c-8) (II-50) (II-a-7) (II-c-8) (II-51) (II-a-1) (II-c-9)(II-52) (II-a-2) (II-c-9) (II-53) (II-a-3) (II-c-9) (II-54) (II-a-5)(II-c-9) (II-55) (II-a-7) (II-c-9) (II-56) (II-a-1) (II-c-10) (II-57)(II-a-3) (II-c-10) (II-58) (II-a-4) (II-c-10) (II-59) (II-a-5) (II-c-10)(II-60) (II-a-6) (II-c-10) (II-61) (II-a-7) (II-c-10) (II-62) (II-a-1)(II-c-11) (II-63) (II-a-2) (II-c-11) (II-64) (II-a-3) (II-c-11) (II-65)(II-a-5) (II-c-11) (II-66) (II-a-7) (II-c-11) (II-67) (II-a-1) (II-c-12)(II-68) (II-a-2) (II-c-12) (II-69) (II-a-3) (II-c-12) (II-70) (II-a-5)(II-c-12) (II-71) (II-a-7) (II-c-12) (II-72) (II-a-1) (II-c-13) (II-73)(II-a-4) (II-c-13) (II-74) (II-a-5) (II-c-13) (II-75) (II-a-6) (II-c-13)(II-76) (II-a-7) (II-c-13) (II-77) (II-a-1) (II-c-14) (II-78) (II-a-2)(II-c-14) (II-79) (II-a-3) (II-c-14) (II-80) (II-a-4) (II-c-14) (II-81)(II-a-5) (II-c-14) (II-82) (II-a-6) (II-c-14) (II-83) (II-a-7) (II-c-14)(II-84) (II-a-1) (II-c-15) (II-85) (II-a-2) (II-c-15) (II-86) (II-a-3)(II-c-15) (II-87) (II-a-5) (II-c-15) (II-88) (II-a-7) (II-c-15) (II-89)(II-a-1) (II-c-16) (II-90) (II-a-2) (II-c-16) (II-91) (II-a-3) (II-c-16)(II-92) (II-a-5) (II-c-16) (II-93) (II-a-7) (II-c-16) (II-94) (II-a-1)(II-c-17) (II-95) (II-a-2) (II-c-17) (II-96) (II-a-3) (II-c-17) (II-97)(II-a-5) (II-c-17) (II-98) (II-a-7) (II-c-17) (II-99) (II-a-1) (II-c-18)(II-100) (II-a-2) (II-c-18) (II-101) (II-a-3) (II-c-18) (II-102)(II-a-5) (II-c-18) (II-103) (II-a-7) (II-c-18) (II-104) (II-a-1)(II-c-19) (II-105) (II-a-2) (II-c-19) (II-106) (II-a-3) (II-c-19)(II-107) (II-a-5) (II-c-19) (II-108) (II-a-7) (II-c-19) (II-109)(II-a-1) (II-c-20) (II-110) (II-a-3) (II-c-20) (II-111) (II-a-4)(II-c-20) (II-112) (II-a-5) (II-c-20) (II-113) (II-a-6) (II-c-20)(II-114) (II-a-7) (II-c-20) (II-115) (II-a-1) (II-c-21) (II-116)(II-a-2) (II-c-21) (II-117) (II-a-3) (II-c-21) (II-118) (II-a-5)(II-c-21) (II-119) (II-a-7) (II-c-21) (II-120) (II-a-1) (II-c-22)(II-121) (II-a-2) (II-c-22) (II-122) (II-a-3) (II-c-22) (II-123)(II-a-5) (II-c-22) (II-124) (II-a-7) (II-c-22)

Among these, preferable examples thereof include the acid generatorsdescribed below.

The acid generator (II) can be produced by a known method in the field.In the formula below, R^(II1), R^(II2), R^(II3), R^(II4), R^(II5),R^(II6), R^(II7), R^(II8), L^(II1), s, n and Y^(II1) represent the samemeaning as described above.

For example, the salt represented by the formula (II) can be obtained byreacting a salt represented by the formula (II-a) with a saltrepresented by the formula (II-b) in a solvent.

Examples of the solvent include chloroform.

The salt represented by the formula (II-b) can be synthesized accordingto the method described in JP-2008-209917A.

The salt represented by the formula (II-a) can be obtained by reacting asalt represented by the formula (II-c) with a compound represented bythe formula (II-d) in a solvent in the presence of a catalyst.

Examples of the solvent include monochloro benzene.

Examples of catalyst include copper (II) dibenzoate.

Examples of the salt represented by the formula (II-c) include diphenyliodonium benzene sulfonate.

Examples of the compound represented by the formula (II-d) includepentamethylene sulfide, 1,4-tioxane, tetrahydrothiophene.

The salt represented by the formula (II) can be also obtained byreacting a salt represented by the formula (II-a′) with a compoundrepresented by the formula (II-b′) in a solvent in the presence ofcatalyst.

Examples of the solvent include monochloro benzene.

Examples of catalyst include copper (II) dibenzoate.

Examples of the salt represented by the formula (II-b′) includepentamethylene sulfide, 1,4-tioxane, tetrahydrothiophene.

The salt represented by the formula (II-a′) can be obtained by reactinga salt represented by the formula (II-c′) with a compound represented bythe formula (II-d′) in a solvent.

Examples of the solvent include chloroform and water.

Examples of the salt represented by the formula (II-c′) includediphenyliodonium chloride.

The salt represented by the formula (II-d′) can be synthesized accordingto the method described in JP-2008-209917A.

In the resist composition of the present invention, the acid generator(II) may be used as a single compound or as a combination of two or morecompounds.

<Acid Generator (III)>

The acid generator (III) which may be included in the resist compositionof the present invention preferably includes a salt represented by theformula (III);

wherein R^(III1) and R^(III2) independently represent a fluorine atom ora C₁ to C₆ perfluoroalkyl group;

L^(III1) represents a single bond or a C₁ to C₁₇ divalent saturatedhydrocarbon group, one or more hydrogen atom in the saturatedhydrocarbon group may be replaced by a fluorine atom or a hydroxy group,and one or more —CH₂— contained in the saturated hydrocarbon group maybe replaced by —O— or —CO—;

Y^(III1) represents an optionally substituted C₁ to C₁₈ alkyl group oran optionally substituted C₃ to C₁₈ alicyclic hydrocarbon group, and oneor more —CH₂— contained in the alkyl group and alicyclic hydrocarbongroup may be replaced by —O—, —CO— or —SO₂—; and

Z⁺ represents an organic cation.

In the formula (III), a moiety having a negative charge in which anorganic cation, Z⁺, having a positive charge is removed may refer to asa sulfonate anion.

Examples of the perfluoroalkyl group of R^(III1) and R^(III2) includetrifluoromethyl, perfluoroethyl, perfluoropropyl, perfluoro-isopropyl,perfluorobutyl, perfluoro-sec-butyl, perfluoro-tert-butyl,perfluoropentyl and perfluorohexyl groups.

Among these, R^(III1) and R^(III2) independently are preferablytrifluoromethyl or fluorine atom, and more preferably a fluorine atom.

Examples of the a divalent saturated hydrocarbon group of L^(III1)include any of;

a chain alkanediyl group such as methylene, ethylene, propane-1,3-diyl,propane-1,2-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl,heptane-1,7-diyl, octane-1,8-diyl, nonane-1,9-diyl, decane-1,10-diyl,undecane-1,11-diyl, dodecane-1,12-diyl, tridecane-1,13-diyl,tetradecane-1,14-diyl, pentadecane-1,15-diyl, hexadecane-1,16-diyl,heptadecane-1,17-diyl, ethane-1,1-diyl, propan-1,1-diyl andpropan-2,2-diyl groups;

a branched chain alkanediyl group such as a group in which a chainalkanediyl group is bonded a side chain of a C₁ to C₄ alkyl group suchas methyl, ethyl, propyl, isopropyl, butyl, sec-butyl and tert-butyl,for example, butane-1,3-diyl, 2-methylpropane-1,3-diyl,2-methylpropane-1,2-diyl, pentane-1,4-diyl and 2-methylbutane-1,4-diylgroups;

a mono-alicyclic hydrocarbon group such as a cycloalkanediyl group,e.g., cyclobutan-1,3-diyl, cyclopentan-1,3-diyl, cyclohexane-1,2-diyl,1-methylhexane-1,2-diyl, cyclohexane-1,4-diyl, cyclooctan-1,2-diyl,cyclooctan-1,5-diyl groups;

a poly-alicyclic hydrocarbon group such as norbornane-2,3-diyl,norbornane-1,4-diyl, norbornane-2,5-diyl, adamantane-1,5-diyl andadamantane-2,6-diyl groups; and a combination of two or more groups.

Examples of the saturated hydrocarbon group of L^(III1) in which one ormore —CH₂— contained in the saturated hydrocarbon group is replaced by—O— or —CO— include groups represented by the formula (b1-1) to theformula (b1-7) below. In the formula (b1-1) to the formula (b1-7), thegroup is represented so as to correspond with two sides of the formula(III), that is, the left side of the group bonds to carbon atom ofC(R^(III1))(R^(III2))— and the right side of the group bonds to —Y(examples of the formula (b1-1) to the formula (b1-7) are the same asabove). * represents a bond.

wherein L^(b2) represents a single bond or a C₁ to C₁₅ divalentsaturated hydrocarbon group;

L^(b3) represents a single bond or a C₁ to C₁₂ divalent saturatedhydrocarbon group;

L^(b4) represents a C₁ to C₁₃ divalent saturated hydrocarbon group, thetotal number of the carbon atoms in L^(b3) and L^(b4) is at most 13;

L^(b5) represents a single bond or a C₁ to C₁₄ divalent saturatedhydrocarbon group;

L^(b6) represents a C₁ to C₁₅ divalent saturated hydrocarbon group, thetotal number of the carbon atoms in L^(b5) and L^(b6) is at most 15;

L^(b7) represents a single bond or a C₁ to C₁₅ divalent saturatedhydrocarbon group;

L^(b8) represents a C₁ to C₁₅ divalent saturated hydrocarbon group, thetotal number of the carbon atoms in L^(b7) and L^(b8) is at most 16;

L^(b9) represents a single bond or a C₁ to C₁₃ divalent saturatedhydrocarbon group;

L^(b10) represents a C₁ to C₁₄ divalent saturated hydrocarbon group, thetotal number of the carbon atoms in L^(b9) and L^(b10) is at most 14;

L^(b11) and L^(b12) independently represent a single bond or a C₁ to C₁₁divalent saturated hydrocarbon group;

L^(b13) represents a C₁ to C₁₂ divalent saturated hydrocarbon group, thetotal number of the carbon atoms in L^(b11), L^(b12) and L^(b13) is atmost 12;

L^(b14) and L^(b15) independently represent a single bond or a C₁ to C₁₃divalent saturated hydrocarbon group;

L^(b16) represents a C₁ to C₁₄ divalent saturated hydrocarbon group, thetotal number of the carbon atoms in L^(b14), L^(b15) and L^(b16) is atmost 14.

Among these, L^(III1) is preferably the groups represented by theformula (b1-1) to the formula (b1-4), more preferably the grouprepresented by the formula (b1-1) or the formula (b1-2), and still morepreferably the group represented by the formula (b1-1). In particular,the divalent group represented by the formula (b1-1) in which L^(b2)represents a single bond or —CH₂— is preferable.

Specific examples of the divalent group represented by the formula(b1-1) include groups below. In the formula below, * represent a bond.

Specific examples of the divalent group represented by the formula(b1-2) include groups below.

Specific examples of the divalent group represented by the formula(b1-3) include groups below.

Specific examples of the divalent group represented by the formula(b1-4) include a group below.

Specific examples of the divalent group represented by the formula(b1-5) include groups below.

Specific examples of the divalent group represented by the formula(b1-6) include groups below.

Specific examples of the divalent group represented by the formula(b1-7) include groups below.

The divalent saturated hydrocarbon group of L^(III1) in which one ormore hydrogen atom in the saturated hydrocarbon group may be replaced bya fluorine atom or a hydroxy group include as follows.

The alkyl group of Y^(III1) is preferably a C₁ to C₆ alkyl group.

Examples of the alicyclic hydrocarbon group of Y^(III1) include groupsrepresented by the formula (Y1) to the formula (Y11) and the formula(Y27) to the formula (Y29) described above.

Y^(III1) may have a substituent.

Examples of the substituent of Y^(III1) include a halogen atom, ahydroxy group, an oxo group, a C₁ to C₁₂ alkyl group, a hydroxygroup-containing C₁ to C₁₂ alkyl group, a C₃ to C₁₆ alicyclichydrocarbon group, a C₁ to C₁₂ alkoxy group, a C₆ to C₁₈ aromatichydrocarbon group, a C₇ to C₂₁ aralkyl group, a C₂ to C₄ acyl group, aglycidyloxy group or a —(CH₂)_(j2)—O—CO—R^(b1) group, wherein R^(b1)represents a C₁ to C₁₆ alkyl group, a C₃ to C₁₆ alicyclic hydrocarbongroup or a C₆ to C₁₈ aromatic hydrocarbon group, j2 represents aninteger of 0 to 4. The alkyl group, alicyclic hydrocarbon group,aromatic hydrocarbon group and the aralkyl group of the substituent mayfurther have a substituent such as a C₁ to C₆ alkyl group, a halogenatom, a hydroxy group and an oxo group.

Examples of the hydroxy group-containing alkyl group includehydroxymethyl and hydroxyethyl groups

Examples of the halogen atom, the alkyl group, the alicyclic hydrocarbongroup, the alkoxyl group, the aromatic hydrocarbon group, the aralkylgroup and the acyl group include the same examples, respectively,described above.

Examples of the alicyclic hydrocarbon group of Y^(III1) in which one ormore —CH₂— contained in the alicyclic hydrocarbon group is replaced by—O—, —CO— or —SO₂— include

a cyclic ether group which is a group in which one or two —CH₂—contained in the alicyclic hydrocarbon group is replaced by the —O—;

an alicyclic hydrocarbon group having an oxo group which is a group inwhich one or two —CH₂— contained in the alicyclic hydrocarbon group isreplaced by the —CO—;

a sultone ring group which is a group in which an adjacent two —CH₂—contained in the alicyclic hydrocarbon group are replaced by the —O— and—SO₂—, respectively;

a lactone ring group which is a group in which an adjacent two —CH₂—contained in the alicyclic hydrocarbon group are replaced by the —O— and—CO—, respectively.

Specific examples of the alicyclic hydrocarbon group of Y^(III1) inwhich one or more —CH₂— contained in the alicyclic hydrocarbon group isreplaced by —O—, —CO— or —SO₂— include groups represented by the formula(Y12) to the formula (Y26) of the above.

Among these, the alicyclic hydrocarbon group is preferably any one ofgroups represented by the formula (Y1) to the formula (Y19), morepreferably any one of groups represented by the formula (Y11), (Y14),(Y15) or (Y19), and still more preferably group represented by theformula (Y11) or (Y14).

Examples of Y^(III1) include the groups below.

Y^(III1) is preferably a C₃ to C₁₂ alicyclic hydrocarbon group which isoptionally substituted, more preferably a C₃ to C₁₂ alicyclichydrocarbon group, still more preferably an adamantyl group which isoptionally substituted, for example, with an oxo group and a hydroxygroup, and further still more preferably an adamantyl group, ahydroxyadamantyl group and an oxoadamantyl group.

The sulfonate anion is preferably an anions represented by the formula(III1-1-1) to the formula (III1-1-11) below. In the formula (III1-1-1)to the formula (III1-11), R^(III1) and R^(III2) and L^(III1) representthe same meaning as defined above. R^(b2) and R^(b3) independentlyrepresent a C₁ to C₄ alkyl group (preferably methyl group).

Specific examples of the sulfonate anion include sulfonate anionsdescribed in JP2010-204646A.

Examples of the cation of the acid generator (III) include an organiconium cation such as an organic sulfonium cation, organic iodoniumcation, organic ammonium cation, benzothiazolium cation and organicphosphonium cation. Among these, organic sulfonium cation and organiciodonium cation are preferable, and aryl sulfonium cation is morepreferable.

Z⁺ of the formula (III) is preferably represented by any of the formula(b2-1) to the formula (b2-4).

wherein R^(b4), R^(b5) and R^(b6) independently represent a C₁ to C₃₀alkyl group, a C₃ to C₁₈ alicyclic hydrocarbon group or a C₆ to C₃₆aromatic hydrocarbon group, or R^(b4) and R^(b5) may be bonded togetherto form a sulfur-containing ring, one or more hydrogen atoms containedin the alkyl group may be replaced by a hydroxy group, a C₃ to C₁₈alicyclic hydrocarbon group, a C₁ to C₁₂ alkoxy group or a C₆ to C₁₈aromatic hydrocarbon group, one or more hydrogen atoms contained in thealicyclic hydrocarbon group may be replaced by a halogen atom, a C₁ toC₁₈ alkyl group, a C₂ to C₄ acyl group and a glycidyloxy group, one ormore hydrogen atoms contained in the aromatic hydrocarbon group may bereplaced by a halogen atom, a hydroxy group or a C₁ to C₁₂ alkoxy group;

R^(b7) and R^(b8) in each occurrence independently represent a hydroxygroup, a C₁ to C₁₂ alkyl group or a C₁ to C₁₂ alkoxyl group;

m2 and n2 independently represent an integer of 0 to 5;

R^(b9) and R^(b10) independently represent a C₁ to C₁₈ alkyl group or aC₃ to C₁₈ alicyclic hydrocarbon group, or R^(b9) and R^(b10) may bebonded together with a sulfur atom bonded thereto to form asulfur-containing 3- to 12-membered (preferably 3- to 7-membered) ring,and one or more —CH₂— contained in the ring may be replaced by —O—, —CO—or —S—;

R^(b11) represents a hydrogen atom, a C₁ to C₁₈ alkyl group, a C₃ to C₁₈alicyclic hydrocarbon group or a C₆ to C₁₈ aromatic hydrocarbon group;

R^(b12) represents a C₁ to C₁₂ alkyl group, a C₃ to C₁₈ alicyclichydrocarbon group or a C₆ to C₁₈ aromatic hydrocarbon group, one or morehydrogen atoms contained in the alkyl group may be replaced by a C₆ toC₁₈ aromatic hydrocarbon group, one or more hydrogen atoms contained inthe aromatic hydrocarbon group may be replaced by a C₁ to C₁₂ alkoxygroup or a C₁ to C₁₂ alkyl carbonyloxy group;

R^(b1) and R^(b12) may be bonded together with —CH—CO— bonded thereto toform a 3- to 12-membered (preferably a 3- to 7-membered) ring, and oneor more —CH₂— contained in the ring may be replaced by —O—, —CO— or —S—;

R^(b13), R^(b14), R^(b15), R^(b16), R^(b17) and R^(b18) in eachoccurrence independently represent a hydroxy group, a C₁ to C₁₂ alkylgroup or a C₁ to C₁₂ alkoxy group;

L^(b11) represents —S— or —O—;

o2, p2, s2 and t2 independently represent an integer of 0 to 5;

q2 or r2 independently represent an integer of 0 to 4;

u2 represents an integer of 0 or 1.

Examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl,n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl and 2-ethylhexylgroups. In particular, the alkyl group of R^(b9) to R^(b11) ispreferably a C₁ to C₁₂ alkyl group.

Examples of the alkyl group in which one or more hydrogen atoms arereplaced by an alicyclic hydrocarbon group include1-(1-adamatane-1-yl)-alkane-1-yl group.

Examples of the alicyclic hydrocarbon group include a monocyclichydrocarbon groups such as cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclodecyl; a polycyclic hydrocarbon groupssuch as decahydronaphtyl, adamantyl and norbornyl (i.e.,bicyclo[2.2.1]heptyl), groups as well as groups below.

In particular, the alicyclic hydrocarbon group of R^(b9) to R^(b11) ispreferably a C₃ to C₁₈ alicyclic hydrocarbon group, and more preferablya C₄ to C₁₂ alicyclic hydrocarbon group.

Examples of the alicyclic hydrocarbon group in which one or morehydrogen atoms are replaced by an alkyl group include methyl cyclohexyl,dimethyl cyclohexyl, 2-alkyladamantan-2-yl, methyl norbornyl andisobornyl groups.

Examples of the aromatic hydrocarbon group include phenyl, naphthyl,anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl,xylyl, cumenyl, mesityl, biphenyl, phenanthryl, 2,6-diethylphenyl and2-methyl-6-ethylphenyl groups.

When the aromatic hydrocarbon include an alkyl group or an alicyclichydrocarbon group, a C₁ to C₁₈ alkyl group or a C₃ to C₁₈ alicyclichydrocarbon group is preferable.

Examples of the alkyl group in which one or more hydrogen atoms arereplaced by an aromatic hydrocarbon group, i.e., aralkyl group includebenzyl, phenethyl, phenylpropyl, trityl, naphthylmethyl andnaphthylethyl groups.

Examples of the alkoxyl group include methoxy, ethoxy, propoxy, propoxy,butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, decyloxy anddodecyloxy groups.

Examples of the halogen atom include fluorine, chlorine, bromine andiodine atoms.

Examples of the acyl group include acetyl, propionyl and butyryl groups.

Examples of the alkyl carbonyloxy group include methyl carbonyloxy,ethyl carbonyloxy, n-propyl carbonyloxy, isopropyl carbonyloxy, n-butylcarbonyloxy, sec-butyl carbonyloxy, tert-butyl carbonyloxy, pentylcarbonyloxy, hexyl carbonyloxy, octylcarbonyloxy and2-ethylhexylcarbonyloxy groups.

The sulfur-containing ring formed by R^(b4) and R^(b5) may be either ofmonocyclic or polycyclic, aromatic or non-aromatic, or saturated orunsaturated ring, and may further have at least one of sulfur atomand/or at least one of oxygen atom as long as the ring has one sulfuratom. The ring is preferably a ring having 3 to 18 carbon atoms, andmore preferably a ring having 4 to 18 carbon atoms.

Examples of the ring having a sulfur atom and formed by R^(b9 and R)^(b10) bonded together include thiolane-1-ium ring(tetrahydrothiophenium ring), thian-1-ium ring and 1,4-oxathian-4-iumring.

Examples of the ring having —CH—CO— and formed by R^(b11) and R^(b12)bonded together include oxocycloheptane ring, oxocyclohexane ring,oxonorbornane ring and oxoadamantane ring.

Among the cations represented by the formula (b2-1) to the formula(b2-4), the cation represented by the formula (b2-1-1) is preferable,and triphenyl sulfonium cation (v2=w2=×2=0 in the formula (b2-1-1)),diphenyl sulfonium cation (v2=w2=0, xz3=1, and R³ is a methyl group inthe formula (b2-1-1)), and tritolyl sulfonium cation (v1=w2=×3=1, P¹, P²and P³ are a methyl group in the formula (b-2-1-1)) are more preferable.

wherein R^(b19), R^(b20) and R^(b21) in each occurrence independentlyrepresent a halogen atom, a hydroxy group, a C₁ to C₁₂ alkyl group, a C₃to C₁₈ alicyclic hydrocarbon group or a C₁ to C₁₂ alkoxy group, or twoof R^(b19), R^(b20) and R^(b21) may be bonded together to form asulfur-containing ring;

v2 to x2 independently represent an integer of 0 to 5.

In the formula (b2-1-1), the sulfur-containing ring formed by two ofR^(b19), R^(b20) and R^(b21) may be either of monocyclic or polycyclic,aromatic or non-aromatic, or saturated or unsaturated ring, and mayfurther have at least one of sulfur atom and/or at least one of oxygenatom as long as the ring has one sulfur atom.

R^(b19) to R^(b21) independently preferably represent a halogen atom(and more preferably fluorine atom), a hydroxy group, a C₁ to C₁₂ alkylgroup or a C₁ to C₁₂ alkoxy group; or two of R^(b19), R^(b20) andR^(b21) preferably are bonded together to form a sulfur-containing ring,and

v2 to x2 independently represent preferably 0 or 1.

Specific examples of the organic cations represented by the formula(b2-1) to the formula (b2-4) include, for example, compounds describedin JP2010-204646A.

The acid generator (III) is a compound combined the above sulfonateanion with an organic cation.

The above sulfonate anion and the organic cation may optionally becombined, a combination of any of the anion represented by the formula(III1-1-1) to the formula (III 1-1-9) and the cation represented by theformula (b2-1-1), as well as a combination of any of the anionrepresented by the formula (III1-1-3) to the formula (III1-1-5) and thecation represented by the formula (b2-3) are preferable.

Preferred acid generators (III) are represented by the formula (III-1)to the formula (III-20). Among these, the formulae (III-1), (III-2),(III-6), (III-11), (III-12), (III-13) and (III-14) which containtriphenyl sulfonium cation, and the formulae (III-3) and (III-7) whichcontain tritolyl sulfonium cation are preferable.

The acid generator (III) can be produced by a known method in thisfield.

In the resist composition of the present invention, the acid generator(III) may be used as a single salt or as a combination of two or moresalts.

<Other Acid Generator>

The resist composition of the present invention contains at least onekinds of acid generator (II), or at least one kinds of acid generator(II) and at lest one kinds of acid generator (III), and may furtherinclude a known acid generator other than the acid generator (II) andthe acid generator (III) (hereinafter is sometimes referred to as “acidgenerator (B)”.

The acid generator (B) may be any of a non-ionic-based and anionic-based acid generator, and ionic-based acid generator ispreferable. Examples of the acid generator (B) include, an acidgenerator having a cation and an anion which are different from these ofthe acid generator (II) and the acid generator (III), an acid generatorhaving a cation which is the same as these of the acid generator (II)and the acid generator (III) and an anion of a known anion which isdifferent from that of the acid generator (II) and the acid generator(III), and an acid generator having an anion which is the same as theseof the acid generator (II) and the acid generator (III) and a cation ofa known anion which is different from that of the acid generator (II)and the acid generator (III).

In the resist composition of the present invention, the proportion ofthe acid generator (II) is preferably not less than 1 weight % (and morepreferably not less than 3 weigh %), and not more than 30 weight % (andmore preferably not more than 25 weight %), with respect to the resin(A).

The proportion of the acid generator (III) is preferably not less than 1weight % (and more preferably not less than 3 weight %), and not morethan 30 weight % (and more preferably not more than 25 weight %), withrespect to the resin (A).

In this case, the weight ratio of the acid generator (II) and the acidgenerator (III) is preferably, for example, 5:95 to 95:5, morepreferably 10:90 to 90:10 and still more preferably 15:85 to 85:15.

When the resist composition of the present invention contains the acidgenerator (B), the total proportion of the acid generator (II), the acidgenerator (III) and the acid generator (B) is preferably not less than 1parts by weight (and more preferably not less than 3 weight %), and notmore than 40 weight % (and more preferably not more than 35 weight %),with respect to the resin (A).

<Solvent (E)>

The resist composition of the present invention preferably includes asolvent (E). The proportion of the solvent (E) 90 weight % or more,preferably 92 weight % or more, and more preferably 94 weight % or more,and also preferably 99.9 weight % or less and more preferably 99 weight% or less. The proportion of the solvent (E) can be measured with aknown analytical method such as, for example, liquid chromatography andgas chromatography.

Examples of the solvent (E) include glycol ether esters such asethylcellosolve acetate, methylcellosolve acetate and propylene glycolmonomethyl ether acetate; glycol ethers such as propylene glycolmonomethyl ether; ethers such as diethylene glycol dimethyl ether;esters such as ethyl lactate, butyl acetate, amyl acetate and ethylpyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanoneand cyclohexanone; and cyclic esters such as γ-butyrolactone. Thesesolvents may be used as a single solvent or as a mixture of two or moresolvents.

<Basic Compound (C)>

The resist composition of the present invention may contain a basiccompound (C). The basic compound (C) is a compound having a property toquench an acid, in particular, generated from the acid generator (B),and called “quencher”.

As the basic compounds (C), nitrogen-containing basic compounds (forexample, amine and basic ammonium salt) are preferable. The amine may bean aliphatic amine or an aromatic amine. The aliphatic amine includesany of a primary amine, secondary amine and tertiary amine. Preferredbasic compounds (C) include compounds presented by the formula (C1) tothe formula (C8) and the formula (C1-1) as described below. Among these,the basic compound presented by the formula (C1-1) is more preferable.

wherein R^(c1), R^(c2) and R^(c3) independently represent a hydrogenatom, a C₁ to C₆ alkyl group, C₅ to C₁₀ alicyclic hydrocarbon group or aC₆ to C₁₀ aromatic hydrocarbon group, one or more hydrogen atomcontained in the alkyl group and alicyclic hydrocarbon group may bereplaced by a hydroxy group, an amino group or a C₁ to C₆ alkoxyl group,one or more hydrogen atom contained in the aromatic hydrocarbon groupmay be replaced by a C₁ to C₆ alkyl group, a C₁ to C₆ alkoxyl group, aC₅ to C₁₀ alicyclic hydrocarbon group or a C₆ to C₁₀ aromatichydrocarbon group.

wherein R^(c2) and R^(c3) have the same definition of the above;

R^(c3) in each occurrence represents a C₁ to C₆ alkyl group, a C₁ to C₆alkoxyl group, a C₅ to C₁₀ alicyclic hydrocarbon group or a C₆ to C₁₀aromatic hydrocarbon group;

m3 represents an integer 0 to 3.

wherein R^(c5), R^(c6), R^(c7) and R^(c8) independently represent theany of the group as described in R^(c1) of the above;

R^(c9) in each occurrence independently represents a C₁ to C₆ alkylgroup, a C₃ to C₆ alicyclic hydrocarbon group or a C₂ to C₆ alkanoylgroup;

n3 represents an integer of 0 to 8.

wherein R^(c10), R^(c11), R^(c12), R^(c13) and R^(c16) independentlyrepresent the any of the groups as described in R^(c1);

R^(c14), R^(c15) and R^(c17) in each occurrence independently representthe any of the groups as described in R^(c1);

o3 and p3 represent an integer of 0 to 3;

L^(c1) represents a divalent C₁ to C₆ alkanediyl group, —CO—, —C(═NH)—,—S— or a combination thereof.

wherein R^(c18), R^(c19) and R^(c20) in each occurrence independentlyrepresent the any of the groups as described in R^(c4);

q3, r3 and s3 represent an integer of 0 to 3;

L^(c2) represents a single bond, a C₁ to C₆ alkanediyl group, —CO—,—C(═NH)—, —S— or a combination thereof.

In the formula (C1) to the formula (C8) and the formula (C1-1), thealkyl, alicyclic hydrocarbon, aromatic, alkoxy and alkanediyl groupsinclude the same examples as the above.

Examples of the alkanoyl group include acetyl, 2-methyl acetyl,2,2-dimethyl acetyl, propionyl, butyryl, isobutyryl, pentanoyl and2,2-dimethyl propionyl groups.

Specific examples of the amine represented by the formula (C1) include1-naphtylamine, 2-naphtylamine, aniline, diisopropylaniline, 2-, 3- or4-methylaniline, 4-nitroaniline, N-methylaniline, N,N-dimethylaniline,diphenylamine, hexylamine, heptylamine, octylamine, nonylamine,decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine,dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine,tripropylamine, tributylamine, tripentylamine, trihexylamine,triheptylamine, trioctylamine, trinonylamine, tridecylamine,methyldibutylamine, methyldipentylamine, methyldihexylamine,methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine,methyldinonylamine, methyldidecylamine, ethyldibutylamine,ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine,ethyldioctylamine, ethyldinonylamine, ethyldidecylamine,dicyclohexylmethylamine, tris[2-(2-methoxyethoxy)ethyl]amine,triisopropanolamine, ethylene diamine, tetramethylene diamine,hexamethylene diamine, 4,4′-diamino-1,2-diphenylethane,4,4′-diamino-3,3′-dimethyldiphenylmethane and4,4′-diamino-3,3′-diethyldiphenylmethane.

Among these, diisopropylaniline is preferable, particularly2,6-diisopropylaniline is more preferable as the basic compounds (C)contained in the present resist composition.

Specific examples of the compound represented by the formula (C2)include, for example, piperazine.

Specific examples of the compound represented by the formula (C3)include, for example, morpholine.

Specific examples of the compound represented by the formula (C4)include, for example, piperidine, a hindered amine compound havingpiperidine skeleton described in JP H11-52575-A.

Specific examples of the compound represented by the formula (C5)include, for example, 2,2′-methylenebisaniline.

Specific examples of the compound represented by the formula (C6)include, for example, imidazole and 4-methylimidazole.

Specific examples of the compound represented by the formula (C7)include, for example, pyridine and 4-methylpyridine.

Specific examples of the compound represented by the formula (C8)include, for example, 1,2-di(2-pyridyl)ethane, 1,2-di(4-pyridyl)ethane,1,2-di(2-pyridyl)ethene, 1,2-di(4-pyridyl)ethene,1,3-di(4-pyridyl)propane, 1,2-di(4-pyridyloxy)ethane,di(2-pyridyl)ketone, 4,4′-dipyridyl sulfide, 4,4′-dipyridyl disulfide,2,2′-dipyridylamine, 2,2′-dipicolylamine and bipyridine.

Examples of the ammonium salt include tetramethylammonium hydroxide,tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide,tetrahexylammonium hydroxide, tetraoctylammonium hydroxide,phenyltrimethyl ammonium hydroxide,3-(trifluoromethyl)phenyltrimethylammonium hydroxide, tetra-n-butylammonium salicylate and choline.

The proportion of the basic compound (C) is preferably 0.01 to 5 weight%, more preferably 0.01 to 3 weight %, and still more preferably 0.01 to1 weight % with respect to the total solid proportion of the resistcomposition.

<Other Ingredient (Hereinafter is Sometimes Referred to as “OtherIngredient (F)”>

The resist composition can also include small amounts of various knownadditives such as sensitizers, dissolution inhibitors, surfactants,stabilizers, and dyes, as needed.

<Preparing the Resist Composition>

The present resist composition can be prepared by mixing the resin (A1),the resin (A2) and the acid generator (B), and the basic compound (C),the solvent (E) and the other ingredient (F) as needed. There is noparticular limitation on the order of mixing. The mixing may beperformed in an arbitrary order. The temperature of mixing may beadjusted to an appropriate temperature within the range of 10 to 40° C.,depending on the kinds of the resin and solubility in the solvent (E) ofthe resin. The time of mixing may be adjusted to an appropriate timewithin the range of 0.5 to 24 hours, depending on the mixingtemperature. There is no particular limitation to the tool for mixing.An agitation mixing may be adopted.

After mixing the above ingredients, the present resist compositions canbe prepared by filtering the mixture through a filter having about 0.003to 0.2 μm pore diameter.

<Method for Producing a Resist Pattern>

The method for producing a resist pattern of the present inventionincludes the steps of:

(1) applying the resist composition of the present invention onto asubstrate;

(2) drying the applied composition to form a composition layer;

(3) exposing the composition layer;

(4) heating the exposed composition layer, and

(5) developing the heated composition layer.

Applying the resist composition onto the substrate can generally becarried out through the use of a resist application device, such as aspin coater known in the field of semiconductor microfabricationtechnique.

Drying the applied composition layer, for example, can be carried outusing a heating device such as a hotplate (so-called “prebake”), adecompression device, or a combination thereof. Thus, the solventevaporates from the resist composition and a composition layer with thesolvent removed is formed. The condition of the heating device or thedecompression device can be adjusted depending on the kinds of thesolvent used. The temperature in this case is generally within the rangeof 50 to 200° C. Moreover, the pressure is generally within the range of1 to 1.0×10⁵ Pa.

The composition layer thus obtained is generally exposed using anexposure apparatus or a liquid immersion exposure apparatus. Theexposure is generally carried out through a mask that corresponds to thedesired pattern. Various types of exposure light source can be used,such as irradiation with ultraviolet lasers such as KrF excimer laser(wavelength: 248 nm), ArF excimer laser (wavelength: 193 nm), F2 excimerlaser (wavelength: 157 nm), or irradiation with far-ultravioletwavelength-converted laser light from a solid-state laser source (YAG orsemiconductor laser or the like), or vacuum ultraviolet harmonic laserlight or the like. Also, the exposure device may be one which irradiateselectron beam or extreme-ultraviolet light (EUV).

After exposure, the composition layer is subjected to a heat treatment(so-called “post-exposure bake”) to promote the deprotection reaction.The heat treatment can be carried out using a heating device such as ahotplate. The heating temperature is generally in the range of 50 to200° C., preferably in the range of 70 to 150° C.

The composition layer is developed after the heat treatment, generallywith an alkaline developing solution and using a developing apparatus.The development here means to bring the composition layer after the heattreatment into contact with an alkaline solution. Thus, the exposedportion of the composition layer is dissolved by the alkaline solutionand removed, and the unexposed portion of the composition layer remainson the substrate, whereby producing a resist pattern. Here, as thealkaline developing solution, various types of aqueous alkalinesolutions used in this field can be used. Examples include aqueoussolutions of tetramethylammonium hydroxide and(2-hydroxyethyl)trimethylammonium hydroxide (common name: choline).

After the development, it is preferable to rinse the substrate and thepattern with ultrapure water and to remove any residual water thereon.

<Application>

The resist composition of the present invention is useful as the resistcomposition for excimer laser lithography such as with ArF, KrF or thelike, and the resist composition for electron beam (EB) exposurelithography and extreme-ultraviolet (EUV) exposure lithography, as wellas liquid immersion exposure lithography.

The resist composition of the present invention can be used insemiconductor microfabrication and in manufacture of liquid crystals,thermal print heads for circuit boards and the like, and furthermore inother photofabrication processes, which can be suitably used in a widerange of applications.

EXAMPLES

The present invention will be described more specifically by way ofexamples, which are not construed to limit the scope of the presentinvention.

All percentages and parts expressing the content or amounts used in theExamples and Comparative Examples are based on weight, unless otherwisespecified.

The structure of a compound is measured by MASS (LC: manufactured byAgilent, 1100 type, MASS: manufactured by Agilent, LC/MSD type or LC/MSDTOF type).

The weight average molecular weight is a value determined by gelpermeation chromatography.

Apparatus: HLC-8120GPCtype (Tosoh Co. Ltd.)

Column: TSK gel Multipore HXL-M×3+guardcolumn (Tosoh Co. Ltd.)

Eluant: tetrahydrofuran

Flow rate: 1.0 mL/min

Detecting device: RI detector

Column temperature: 40° C.

Injection amount: 100 μL

Standard material for calculating molecular weight: standard polystylene(Toso Co. ltd.)

Synthesis Example 1 Synthesis of Compound Represented by the Formula (A)

9.60 parts of a compound (A-2), 38.40 parts of tetrahydrofuran and 5.99parts of pyridine were mixed, and stirred for 30 minutes at 23° C. Theobtained mixture was cooled to 0° C. To this mixture, 14.00 parts of acompound (A-1) was added over 1 hour while maintaining at the sametemperature. The temperature of the mixture was then elevated to about10° C., and the mixture was stirred for 1 hour at the same temperature.To the obtained reactant including a compound (A-3), 14.51 parts of acompound of (A-4), 1-(3-dimethylaminopropyl)-3-ethyl carbodiimidehydrochloride, and 8.20 parts of a compound of (A-5) were added, andstirred for 3 hours at 23° C. 271.95 parts of ethyl acetate and 16.57parts of 5% of hydrochloric acid solution were added to the obtainedmixture, the mixture was stirred for 30 minutes at 23° C. The obtainedsolution was allowed to stand, and then separated to recover an organiclayer. To the recovered organic layer, 63.64 parts of a saturated sodiumhydrogen carbonate was added, and the obtained solution was stirred for30 minutes at 23° C., allowed to stand, and then separated to wash theorganic layer. These washing operations were repeated for 2 times. Tothe washed organic layer, 67.99 parts of ion-exchanged water was added,and the obtained solution was stirred for 30 minutes at 23° C., allowedto stand, and then separated to wash the organic layer with water. Thesewashing operations were repeated for 5 times. The obtained organic layerwas concentrated, to the obtained concentrate, 107.71 parts of ethylacetate was added, stirred to dissolve the concentrate completely, and64.26 parts of n-heptane was added in the form of drops to this. Afteraddition, the obtained mixture was stirred for 30 minutes at 23° C., andfiltrated, resulting in 15.11 parts of the compound (A).

MS (mass spectroscopy): 486.2 (molecular ion peak)

Synthesis Example 2 Synthesis of Compound Represented by the Formula (B)

6.32 parts of a compound (B-2), 30.00 parts of tetrahydrofuran and 5.99parts of pyridine were mixed, and stirred for 30 minutes at 23° C. Theobtained mixture was cooled to 0° C. To this mixture, 14.00 parts of acompound (B-1) was added over 1 hour while maintaining at the sametemperature. The temperature of the mixture was then elevated to about10° C., and the mixture was stirred for 1 hour at the same temperature.To the obtained reactant including a compound (B-3), 14.51 parts of acompound of (B-4), 1-(3-dimethylaminopropyl)-3-ethyl carbodiimidehydrochloride, and 8.20 parts of a compound of (B-5) were added, andstirred for 3 hours at 23° C. 270.00 parts of ethyl acetate and 16.57parts of 5% of hydrochloric acid solution were added to the obtainedmixture, the mixture was stirred for 30 minutes at 23° C. The obtainedsolution was allowed to stand, and then separated to recover an organiclayer. To the recovered organic layer, 65.00 parts of a saturated sodiumhydrogen carbonate was added, and the obtained solution was stirred for30 minutes at 23° C., allowed to stand, and then separated to wash theorganic layer. These washing operations were repeated for 2 times. Tothe washed organic layer was added 65.00 parts of ion-exchanged water,and the obtained solution was stirred for 30 minutes at 23° C., allowedto stand, and then separated to wash the organic layer with water. Thesewashing operations were repeated for 5 times. The obtained organic layerwas concentrated, to the obtained concentrate, and separated by a column(condition; stationary phase: silica gel 60-200 mesh manufactured byMerk, developing solvent: n-heptane/ethyl acetate), resulting in 9.90parts of the compound (B).

MS (mass spectroscopy): 434.1 (molecular ion peak)

Synthesis Example 3 Synthesis of Compound Represented by the Formula (C)

7.08 parts of a compound (C-2), 30.00 parts of tetrahydrofuran and 5.99parts of pyridine were mixed, and stirred for 30 minutes at 23° C. Theobtained mixture was cooled to 0° C. To this mixture, 14.00 parts of acompound (C-1) was added over 1 hour while maintaining at the sametemperature. The temperature of the mixture was then elevated to about10° C., and the mixture was stirred for 1 hour at the same temperature.To the obtained reactant including a compound (C-3), 14.51 parts of acompound of (C-4), 1-(3-dimethylaminopropyl)-3-ethyl carbodiimidehydrochloride, and 8.20 parts of a compound of (C-5) were added, andstirred for 3 hours at 23° C. 270.00 parts of ethyl acetate and 16.57parts of 5% of hydrochloric acid solution were added to the obtainedmixture, the mixture was stirred for 30 minutes at 23° C. The obtainedsolution was allowed to stand, and then separated to recover an organiclayer. To the recovered organic layer, 65.00 parts of a saturated sodiumhydrogen carbonate was added, and the obtained solution was stirred for30 minutes at 23° C., allowed to stand, and then separated to wash theorganic layer. These washing operations were repeated for 2 times. Tothe washed organic layer was added 65.00 parts of ion-exchanged water,and the obtained solution was stirred for 30 minutes at 23° C., allowedto stand, and then separated to wash the organic layer with water. Thesewashing operations were repeated for 5 times. The obtained organic layerwas concentrated, to the obtained concentrate, and separated by a column(condition; stationary phase: silica gel 60-200 mesh manufactured byMerk, developing solvent: n-heptane/ethyl acetate), resulting in 10.24parts of the compound (C).

MS (mass spectroscopy): 446.1 (molecular ion peak)

Synthesis Example 4 Synthesis of Compound Represented by the Formula (E)

25 parts of a compound (E-1) and 25 parts of tetrahydrofuran were mixed,and stirred for 30 minutes at 23° C. The obtained mixture was cooled to0° C. To this mixture, 10.2 parts of a compound (E-2), 11.2 parts ofpyridine and 30 parts of tetrahydrofuran were added over 1 hour whilemaintaining at the same temperature. The temperature of the mixture wasthen elevated to about 25° C., and the mixture was stirred for 1 hour atthe same temperature. To the obtained reactant, 200 parts of a ethylacetate and 50 parts of ion-exchanged-water were added, stirred, andthen separated to recover an organic layer. The obtained organic layerwas concentrated, to this concentrate, 500 parts of n-heptane was addedto obtain a solution, and the solution was stirred and filtrated,resulting in 40.18 parts of a compound (E-3). 35.21 parts of thecompound (E-3), 160 parts of tetrahydrofuran, 22.8 parts of the compound(E-5) and 8.3 parts of pyridine were charged, and stirred for 30 minutesat 23° C. The obtained mixture was cooled to 0° C. To the obtainedmixture, 33.6 parts of a compound of (E-4),1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride, and 140parts of chloroform were added, and stirred for 18 hours at 23° C. Tothis reactant solution, 850 parts of n-heptane and 77 parts of 5% ofhydrochloric acid solution were added, the mixture was stirred for 30minutes at 23° C. The obtained solution was allowed to stand, and thenseparated to recover an organic layer. To the recovered organic layer,61 parts of 10% potassium carbonate was added, and the obtained solutionwas stirred for 30 minutes at 23° C., allowed to stand, and thenseparated to wash the organic layer. These washing operations wererepeated for 2 times. To the washed organic layer, 230 parts ofion-exchanged water was added, and the obtained solution was stirred for30 minutes at 23° C., allowed to stand, and then separated to wash theorganic layer with water. These washing operations were repeated for 5times. The obtained organic layer was concentrated, resulting in 31.5parts of the compound (E).

MS (mass spectroscopy): 420.1 (molecular ion peak)

Synthesis Example 5 Synthesis of Compound Represented by the Formula (F)

25.00 parts of a compound (F-1) and 25.00 parts of tetrahydrotetrahydrofuran were mixed, and stirred for 30 minutes at 23° C. Theobtained mixture was cooled to 0° C. To this mixture, a mixture of 8.50parts of a compound (F-2), 25.00 parts of tetrahydrofuran and 11.2 partsof pyridine was added, over 1 hour while maintaining at the sametemperature. The temperature of the mixture was then elevated to about25° C., and the mixture was stirred for 1 hour at the same temperature.To the obtained reactant, 190 parts of ethyl acetate and 50 parts ofion-exchanged water were added, and then separated to recover an organiclayer. The obtained organic layer was concentrated. To the obtainedconcentrate, 150.0 parts of n-heptane was added, and the obtainedmixture was stirred, and the supernatant was removed. The obtainedmixture was concentrated, resulting in 28.7 parts of the compound (F-3).

19.80 parts of a compound (F-3), 90.0 parts of tetrahydrofuran, 10.3parts of a compound (F-5) and 5.0 parts of pyridine were mixed, andstirred for 30 minutes at 23° C. The obtained mixture was cooled to 0°C. To this mixture, 15.2 parts of a compound (F-4),1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride, was added,and stirred for 18 hours at 23° C. 450.0 parts of n-heptane and 47.0parts of 5% of hydrochloric acid solution were added to the obtainedmixture, the mixture was stirred for 30 minutes at 23° C. The obtainedsolution was allowed to stand, and then separated to recover an organiclayer. To the recovered organic layer, 37.0 parts of 10% potassiumcarbonate was added, and the obtained solution was stirred for 30minutes at 23° C., allowed to stand, and then separated to wash theorganic layer. These washing operations were repeated for 2 times. Tothe washed organic layer, 120.0 parts of ion-exchanged water was added,and the obtained solution was stirred for 30 minutes at 23° C., allowedto stand, and then separated to wash the organic layer with water. Thesewashing operations were repeated for 5 times. The obtained organic layerwas concentrated to the obtained concentrate, resulting in 20.1 parts ofthe compound (F).

MS (mass spectroscopy): 406.1 (molecular ion peak)

Synthesis Example 6 Synthesis of Compound Represented by the Formula(II-2)

A compound represented by the formula (II-2-b) was synthesized accordingto the method described in JP 2008-209917A.

35.00 parts of the compound represented by the formula (II-2-b), 30.58parts of the salt represented by the formula (II-2-a), 100 parts ofchloroform and 50.00 parts of ion-exchanged water were charged, andstirred for 15 hours at 23° C. The obtained reacted solution wasseparated into two layers, and a chloroform layer was isolated. To theobtained chloroform layer, 30 parts of ion-exchanged water was added,stirred, and separated to wash an organic layer. These operations wererepeated for five times. The obtained chloroform layer was concentratedto obtain a concentrate, to this concentrate, 100 parts oftert-butylmethyl ether was added, and the obtained mixture was stirredfor 30 minutes at 23° C., and filtrated, resulting in 44.93 parts of thesalt represented by the formula (II-2-c).

20.0 parts of the salt represented by the formula (II-2-c), 3.36 partsof the compound represented by the formula (II-2-d) and 100.00 parts ofmonochlorobenzene were charged, and stirred for 30 minutes at 23° C.,0.25 parts of cupper (II) dibenzoate was added thereto. The resultantwas stirred for 1 hour at 100° C. to obtain the solution. The obtainedreacted solution was concentrated. To the obtained residue, 200 parts ofchloroform, 8 parts of acetonitrile and 50 parts of ion-exchanged waterwere added, stirred for 30 minutes at 23° C., and separated to obtain anorganic layer. To the obtained organic layer, 50 parts of ion-exchangedwater was added, stirred for 30 minutes at 23° C., and separated toobtain an organic layer. These operations repeated for four times. Theobtained organic layer was concentrated to obtain a concentrate, to thisconcentrate, 37 parts of acetonitrile was added to dissolve, and theobtained mixture was concentrated. To the obtained residue, 71.80 partsof tert-butyl methyl ether was added, stirred, and the supernatant wasremoved. To the obtained mass, acetonitrile was added to dissolve, andconcentrated, resulting in 2.44 parts of the salt represented by theformula (II-2).

MS (ESI(+) Spectrum): M⁺ 181.1

MS (ESI(−) Spectrum): M⁻ 339.1

Synthesis Example 7 Synthesis of Compound Represented by the Formula(II-3)

The compound represented by the formula (II-3-b) was synthesizedaccording to the method described in JP 2008-209917A.

30.00 parts of the compound represented by the formula (II-3-b), 30.50parts of the salt represented by the formula (II-3-a), 100 parts ofchloroform and 50.00 parts of ion-exchanged water were charged, andstirred for 15 hours at 23° C. The obtained reacted solution wasseparated into two layers, and a chloroform layer was isolated. To theobtained chloroform layer, 30 parts of ion-exchanged water was added,stirred, and separated to wash an organic layer. These operations wererepeated for five times. To the obtained chloroform layer wasconcentrated to obtain a concentrate, to this concentrate, 100 parts oftert-butylmethyl ether was added, and the obtained mixture was stirredfor 30 minutes at 23° C., and filtrated, resulting in 48.57 parts of thesalt represented by the formula (II-2-c).

20.0 parts of the salt represented by the formula (II-3-c), 2.86 partsof the compound represented by the formula (II-3-d) and 250.00 parts ofmonochlorobenzene were charged, and stirred for 30 minutes at 23° C.,0.21 parts of cupper (II) dibenzoate was added thereto. The resultantwas stirred for 1 hour at 100° C. to obtain the solution. The obtainedreacted solution was concentrated. To the obtained residue, 200 parts ofchloroform and 50 parts of ion-exchanged water were added, stirred for30 minutes at 23° C., and separated to obtain an organic layer. To theobtained organic layer, 50 parts of ion-exchanged water were added,stirred for 30 minutes at 23° C., and separated to obtain an organiclayer. These operations repeated for five times. The obtained organiclayer was concentrated to obtain a concentrate, to this concentrate,53.51 parts of acetonitrile was added to dissolve, and the obtainedmixture was concentrated. To the obtained residue, 113.05 parts oftert-butyl methyl ether was added, stirred, and filtrated to obtain10.47 parts of the salt represented by the formula (II-3).

MS (ESI(+) Spectrum): M⁺ 237.1

MS (ESI(−) Spectrum): M⁻ 339.1

Synthesis Example 8 Synthesis of Compound Represented by the Formula(III-5)

50.49 parts of the compound represented by the formula (III-5-a) and252.4 parts of chloroform were charged, and stirred for 30 minutes at23° C. To the obtained reacted solution, 16.27 parts of the compoundrepresented by the formula (III-5-b) was added in the form of drops, andstirred for 1 hour at 23° C. to obtain a solution containing thecompound represented by the formula (III-5-c). To the solution, 48.80parts of the salt represented by the formula (III-5-d) and 84.15 partsof the ion-exchanged water were added, stirred for 12 hours at 23° C.The obtained reacted solution was separated into two layers, and achloroform layer was isolated. To the obtained chloroform layer, 84.15parts of ion-exchanged water was added, stirred, and separated to washan organic layer. These operations were repeated for five times. To theobtained chloroform layer, 3.88 parts of activated carbon was added, andthe mixture was stirred and filtrated. The filtrate was concentrated toobtain a concentrate, to this concentrate, 125.87 parts of acetonitrilewas added, and the obtained mixture was concentrated. To the obtainedresidue, 20.6 parts of acetonitrile and 309.30 parts of tert-butylmethyl ether were added, stirred for 30 minutes at 23° C. Thesupernatant was removed, the obtained solution was concentrated toobtain a concentrate, to this concentrate, 200 parts of n-heptane wasadded, and the obtained mixture was stirred for 30 minutes at 23° C.,and filtrated, resulting in 61.54 parts of the salt represented by theformula (II-5).

MS (ESI(+) Spectrum): M⁺ 375.2

MS (ESI(−) Spectrum): M⁻ 339.1

Synthesis Example 9 Synthesis of Compound Represented by the Formula(III-19)

5.00 parts of the compound represented by the formula (III-19-a) and 25parts of dimethylformamide were charged, and stirred for 30 minutes at23° C. To the obtained reacted solution, 3.87 parts of trimethylaminewas added in the form of drops, and stirred for 30 minutes at 23° C. toobtain a mixture. To the mixture, a solution dissolved 6.14 parts thesalt represented by the formula (III-19-b) in 6.14 parts ofdimethylformamide was added over 30 minutes, stirred for 2 hours at 23°C. To the obtained reacted solution, 25 parts of ion-exchanged water and150 parts of ethyl acetate were added, the obtained mixture was stirredfor 30 minutes at 23° C., and separated to obtain an organic layer. Tothe obtained organic layer, 75 parts of ion-exchanged water was added,the obtained mixture was stirred for 30 minutes at 23° C., and separatedto obtain an organic layer. These washing operations repeated for fivetimes. The obtained organic layer was concentrated to obtain aconcentrate, to this concentrate, 92.20 parts of n-heptane was added,stirred, and filtrated, resulting in 2.69 parts of the salt representedby the formula (III-19-c).

The compound represented by the formula (III-19-d) was synthesizedaccording to the method described in JP 2008-127367A.

2.99 parts of the salt represented by the formula (III-19-d), 15.00parts of acetonitrile were charged, and stirred for 30 minutes at 23° C.To the obtained reacted solution, 1.30 parts of the compound representedby the formula (III-19-e) was added, and stirred for 2 hours at 70° C.The obtained reactant was cooled to 23° C., and filtrated to obtain asolution containing the compound represented by the formula (III-19-f).To the obtained solution, a solution dissolved 2.12 parts of a compound(III-19-c) in 6.36 parts of chloroform was charged, stirred for 23 hoursat 23° C. The obtained reactant was concentrated to obtain concentrate,to this concentrate, 60 parts of chloroform and 30 parts of 2% oxalicacid solution were charged, stirred, and then separated to recover anorganic layer. These washing operations were repeated for two times. Tothe recovered organic layer, 30 parts of ion-exchanged water was added,and the obtained solution was stirred, and then separated to wash theorganic layer with water. These washing operations were repeated forfive times. The obtained organic layer was concentrated, to thisconcentrate, 30 parts of acetonitrile was added to dissolve, andconcentrated. To this concentrate, 50 parts of tert-butylmethyl etherwas added, stirred, and the supernatant was removed. The obtainedresidue was dissolved in acetonitrile, and the obtained solution wasconcentrated, resulting in 3.46 parts of the salt represented by theformula (III-19).

MS (ESI(+) Spectrum): M⁺ 263.1

MS (ESI(−) Spectrum): M⁻ 517.2

Synthetic Example of the Resin

The monomers used the synthesis of the resin are shown below.

These monomers are referred to as “monomer (a1-1-1)” to “monomer (F)”.

Synthetic Example 10 Synthesis of Resin A1-1

Monomer (a-4-1-7) and monomer (A) were mixed together with a mole ratioof Monomer (a-4-1-7): monomer (A)=90:10, and dioxane was added theretoin an amount equal to 1.5 times by weight of the total amount ofmonomers to obtain a solution. Azobisisobutyronitrile andazobis(2,4-dimethylvaleronitrile) was added as an initiator to obtain asolution in an amount of 0.7 mol % and 2.1 mol % respectively withrespect to the entire amount of monomers, and the resultant mixture washeated for about 5 hours at 75° C. After that, the obtained reactedmixture was poured into a large amount of methanol/water mixed solventto precipitate a resin. The obtained resin was filtrated. Thus obtainedresin was dissolved in another dioxane to obtain a solution, and thesolution was poured into a mixture of methanol/water mixed solvent toprecipitate a resin. The obtained resin was filtrated. These operationswere repeated for two times, resulting in a 82% yield of copolymerhaving a weight average molecular weight of about 17000. This copolymer,which had the structural units of the following formula, was referred toResin A1-1.

Synthetic Example 11 Synthesis of Resin A1-2

Monomer (B) was used, and dioxane was added thereto in an amount equalto 1.5 times by weight of the total amount of monomers to obtain asolution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile)was added as an initiator to obtain a solution in an amount of 0.7 mol %and 2.1 mol % respectively with respect to the entire amount ofmonomers, and the resultant mixture was heated for about 5 hours at 75°C. After that, the obtained reacted mixture was poured into a largeamount of methanol/water mixed solvent to precipitate a resin. Thusobtained resin was dissolved in another dioxane to obtain a solution,and the solution was poured into a mixture of methanol/water mixedsolvent to precipitate a resin. The obtained resin was filtrated. Theseoperations were repeated for two times, resulting in a 85% yield ofpolymer having a weight average molecular weight of about 20000. Thispolymer, which had the structural units of the following formula, wasreferred to Resin A1-2.

Synthetic Example 12 Synthesis of Resin A1-3

Monomer (C) was used, and dioxane was added thereto in an amount equalto 1.5 times by weight of the total amount of monomers to obtain asolution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile)was added as an initiator to obtain a solution in an amount of 0.7 mol %and 2.1 mol % respectively with respect to the entire amount ofmonomers, and the resultant mixture was heated for about 5 hours at 75°C. After that, the obtained reacted mixture was poured into a largeamount of methanol/water mixed solvent to precipitate a resin. Thusobtained resin was dissolved in another dioxane to obtain a solution,and the solution was poured into a mixture of methanol/water mixedsolvent to precipitate a resin. The obtained resin was filtrated. Theseoperations were repeated for two times, resulting in a 83% yield ofpolymer having a weight average molecular weight of about 19000. Thispolymer, which had the structural units of the following formula, wasreferred to Resin A1-3.

Synthetic Example 13 Synthesis of Resin A1-4

Monomer (E) was used, and dioxane was added thereto in an amount equalto 1.2 times by weight of the total amount of monomers to obtain asolution. Azobis(2,4-dimethylvaleronitrile) was added as an initiator toobtain a solution in an amount of 4.5 mol % with respect to the entireamount of monomers, and the resultant mixture was heated for about 5hours at 60° C. After that, the obtained reacted mixture was poured intoa large amount of n-heptane to precipitate a resin. The obtained resinwas filtrated, resulting in a 89% yield of polymer having a weightaverage molecular weight of about 26000. This polymer, which had thestructural units of the following formula, was referred to Resin A1-4.

Synthetic Example 14 Synthesis of Resin A1-5

Monomer (F) was used, and dioxane was added thereto in an amount equalto 1.2 times by weight of the total amount of monomers to obtain asolution. Azobis(2,4-dimethylvaleronitrile) was added as an initiator toobtain a solution in an amount of 4.5 mol % with respect to the entireamount of monomers, and the resultant mixture was heated for about 5hours at 60° C. After that, the obtained reacted mixture was poured intoa large amount of n-heptane to precipitate a resin. The obtained resinwas filtrated, resulting in a 90% yield of polymer having a weightaverage molecular weight of about 3.9000. This polymer, which had thestructural units of the following formula, was referred to Resin A1-5.

Synthetic Example 15 Synthesis of Resin A2-1

Monomer (a1-1-3), monomer (a1-2-3), monomer (a2-1-1), monomer (a3-1-1)and monomer (a3-2-3) were charged with molar ratio 30:14:6:20:30, anddioxane was added thereto in an amount equal to 1.5 weight times of thetotal amount of monomers to obtain a solution. Azobisisobutyronitrileand azobis(2,4-dimethylvaleronitrile) was added as an initiator theretoin an amount of 1 mol % and 3 mol % respectively with respect to theentire amount of monomers, and the resultant mixture was heated forabout 5 hours at 73° C. After that, the reaction solution was pouredinto a mixture of methanol and ion-exchanged water (4:1) in largeamounts to precipitate a resin. The obtained resin was filtrated. Thusobtained resin was dissolved in another dioxane to obtain a solution,and the solution was poured into a large amount of a mixture of methanoland water to precipitate a resin. The obtained resin was filtrated.These operations were repeated two times for purification, resulting in65% yield of copolymer having a weight average molecular weight of about8100. This copolymer, which had the structural units derived from themonomers of the following formula, was designated Resin A2-1.

Synthetic Example 16 Synthesis of Resin A2-2

Monomer (a1-1-2), monomer (a1-2-3), monomer (a2-1-1), monomer (a3-1-1)and monomer (a3-2-3) were charged with molar ratio 30:14:6:20:30, anddioxane was added thereto in an amount equal to 1.5 weight times of thetotal amount of monomers to obtain a solution. Azobisisobutyronitrileand azobis(2,4-dimethylvaleronitrile) was added as an initiator theretoin an amount of 1 mol % and 3 mol % respectively with respect to theentire amount of monomers, and the resultant mixture was heated forabout 5 hours at 73° C. After that, the reaction solution was pouredinto a mixture of methanol and ion-exchanged water (4:1) in largeamounts to precipitate a resin. The obtained resin was filtrated. Thusobtained resin was dissolved in another dioxane to obtain a solution,and the solution was poured into a large amount of a mixture of methanoland water to precipitate a resin. The obtained resin was filtrated.These operations were repeated two times for purification, resulting in68% yield of copolymer having a weight average molecular weight of about7800. This copolymer, which had the structural units derived from themonomers of the following formula, was designated Resin A2-2.

Synthetic Example 17 Synthesis of Resin A2-3

Monomer (a1-1-2), monomer (a2-1-1) and monomer (a3-1-1) were mixed withmolar ratio 50:25:25, and dioxane was added thereto in an amount equalto 1.5 weight times of the total amount of monomers.Azobisisobutyronitrile and azobis(2,4-dimethyl valeronitrile) was addedas an initiator thereto in an amount of 1 mol % and 3 mol % respectivelywith respect to the entire amount of monomers, and the resultant mixturewas heated for about 8 hours at 80° C. After that, the reaction solutionwas poured into a mixture of methanol and ion-exchanged water (4:1) inlarge amounts to precipitate a resin. The obtained resin was filtrated.Thus obtained resin was dissolved in another dioxane to obtain asolution, and the solution was poured into a large amount of a mixtureof methanol and water to precipitate a resin. The obtained resin wasfiltrated. These operations were repeated three times for purification,resulting in 60% yield of copolymer having a weight average molecularweight of about 9200. This copolymer, which had the structural unitsderived from the monomers of the following formulae, was designatedResin A2-3.

Synthetic Example 18 Synthesis of Resin A2-4

Monomer (a1-1-3), monomer (a1-2-3), monomer (a2-1-1), monomer (a3-2-3)and monomer (a3-1-1) were charged with molar ratio 30:14:6:20:30, anddioxane was added thereto in an amount equal to 1.5 weight times of thetotal amount of monomers to obtain a solution. Azobisisobutyronitrileand azobis(2,4-dimethylvaleronitrile) was added as an initiator theretoin an amount of 1 mol % and 3 mol % respectively with respect to theentire amount of monomers, and the resultant mixture was heated forabout 5 hours at 75° C. After that, the reaction solution was pouredinto a mixture of methanol and ion-exchanged water (4:1) in largeamounts to precipitate a resin. The obtained resin was filtrated. Thusobtained resin was dissolved in another dioxane to obtain a solution,and the solution was poured into a large amount of a mixture of methanoland water to precipitate a resin. The obtained resin was filtrated.These operations were repeated two times for purification, resulting in60% yield of copolymer having a weight average molecular weight of about7000. This copolymer, which had the structural units derived from themonomers of the following formula, was designated Resin A2-4.

Synthetic Example 19 Synthesis of Resin A2-5

Monomer (a1-1-3), monomer (a1-5-1), monomer (a2-1-1), monomer (a3-2-3)and monomer (a3-1-1) were charged with molar ratio 30:14:6:20:30, anddioxane was added thereto in an amount equal to 1.5 weight times of thetotal amount of monomers to obtain a solution. Azobisisobutyronitrileand azobis(2,4-dimethylvaleronitrile) was added as an initiator theretoin an amount of 1 mol % and 3 mol % respectively with respect to theentire amount of monomers, and the resultant mixture was heated forabout 5 hours at 75° C. After that, the reaction solution was pouredinto a mixture of methanol and ion-exchanged water in large amounts toprecipitate a resin. The obtained resin was filtrated. Thus obtainedresin was dissolved in another dioxane to obtain a solution, and thesolution was poured into a large amount of a mixture of methanol andwater to precipitate a resin. The obtained resin was filtrated. Theseoperations were repeated two times for purification, resulting in 62%yield of copolymer having a weight average molecular weight of about7400. This copolymer, which had the structural units derived from themonomers of the following formula, was designated Resin A2-5.

Synthetic Example 20 Synthesis of Resin X1

Monomer (a1-1-1), monomer (a3-1-1) and monomer (a2-1-1) were mixed withmolar ratio 35:45:20, and dioxane was added thereto in an amount equalto 1.5 times by weight of the total amount of monomers to obtain asolution. Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile)was added as an initiator to obtain a solution in an amount of 1.0 mol %and 3.0 mol % respectively with respect to the entire amount ofmonomers, and the resultant mixture was heated for about 5 hours at 75°C. After that, the obtained reacted mixture was poured into a mixture ofa large amount of methanol and water to precipitate a resin. Theobtained resin was filtrated. Thus obtained resin was dissolved inanother dioxane to obtain a solution, and the solution was poured into amixture of methanol and water to precipitate a resin. The obtained resinwas filtrated. These operations were repeated 2 times for purification,resulting in a 75% yield of copolymer having a weight average molecularweight of about 7000. This copolymer, which had the structural units ofthe following formula, was referred to Resin X1.

Synthetic Example 21 Synthesis of Resin X2

Monomer (D) and monomer (a1-1-1) were mixed with molar ratio=80:20, anddioxane was added thereto in an amount equal to 1.5 times by weight ofthe total amount of monomers to obtain a solution.Azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) was addedas an initiator to obtain a solution in an amount of 0.5 mol % and 1.5mol % respectively with respect to the entire amount of monomers, andthe resultant mixture was heated for about 5 hours at 70° C. After that,the obtained reacted mixture was poured into a mixture of a large amountof methanol and water to precipitate a resin. The obtained resin wasfiltrated. Thus obtained resin was dissolved in another dioxane toobtain a solution, and the solution was poured into a mixture ofmethanol and ion-exchanged water to precipitate a resin. The obtainedresin was filtrated. These operations were repeated 2 times, resultingin a 70% yield of copolymer having a weight average molecular weight ofabout 28000. This copolymer, which had the structural units of thefollowing formula, was referred to Resin X2.

(Preparing Resist Composition)

Resist compositions were prepared by mixing and dissolving each of thecomponents shown in Table 2, and then filtrating through a fluororesinfilter having 0.2 μm pore diameter.

TABLE 2 (Unit: parts) Basic BP/PEB Resin Acid Generator Compound (° C.)Ex. 1 A1-1/A2-1 = II-2/III-3 = 0.80/0.70 C1 = 0.07 95/85 0.7/10 2A1-1/A2-2 = II-2/III-3 = 0.80/0.70 C1 = 0.07 110/105 0.7/10 3 A1-1/A2-3= II-2/III-3 = 0.80/0.70 C1 = 0.07 110/105 0.7/10 4 A1-2/A2-1 =II-2/III-3 = 0.80/0.70 C1 = 0.07 95/85 0.7/10 5 A1-2/A2-2 = II-2/III-3 =0.80/0.70 C1 = 0.07 110/105 0.7/10 6 A1-2/A2-3 = II-2/III-3 = 0.80/0.70C1 = 0.07 110/105 0.7/10 7 A1-3/A2-1 = II-2/III-3 = 0.80/0.70 C1 = 0.0795/85 0.7/10 8 A1-3/A2-2 = II-2/III-3 = 0.80/0.70 C1 = 0.07 110/1050.7/10 9 A1-3/A2-3 = II-2/III-3 = 0.80/0.70 C1 = 0.07 110/105 0.7/10 10 A1-2/A2-1 = II-3/III-3 = 0.80/0.70 C1 = 0.07 95/85 0.7/10 11  A1-2/A2-2= II-3/III-3 = 0.80/0.70 C1 = 0.07 110/105 0.7/10 12  A1-2/A2-3 =II-3/III-3 = 0.80/0.70 C1 = 0.07 110/105 0.7/10 13  A1-2/X1 = II-2/B1 =0.1/1.0 C1 = 0.07 110/105 0.3/10 14  A1-1/A2-4 = II-3/III-3 = 0.80/0.70C1 = 0.07 95/85 0.7/10 15  A1-1/A2-5 = II-3/III-3 = 0.80/0.70 C1 = 0.0795/85 0.7/10 16  A1-4/A2-5 = II-3/III-3 = 0.80/0.70 C1 = 0.07 95/850.7/10 17  A1-5/A2-5 = II-3/III-3 = 0.80/0.70 C1 = 0.07 95/85 0.7/10 18 A1-1/A2-5 = II-3/III-5 = 0.80/0.70 C1 = 0.07 95/85 0.7/10 19  A1-1/A2-5= II-3/III-19 = 0.80/0.70 C1 = 0.07 95/85 0.7/10 Com- parative Ex. 1X2/X1 = B1/B2 = 1.0/0.1 C1 = 0.07 110/105 0.3/10<Resin>

Resins Prepared by the Synthetic Examples

<Acid Generator>

B1: this was prepared by a method according to the method described inthe Examples of JP2010-152341A

B2: this was prepared by a method according to the method described inthe Examples of WO2008/99869 and JP2010-26478A

B3: this was prepared by a method according to the method described inthe Examples of JP2005-221721A

<Basic Compound: Qencher>

C1: 2,6-diisopropylaniline (obtained from Tokyo Chemical Industry Co.,LTD)

<Solvent of Resist Composition>

Propylene glycol monomethyl ether acetate 265 parts  Propylene glycolmonomethyl ether 20 parts 2-Heptanone 20 parts γ-butyrolactone 3.5parts (Producing Resist Pattern)

A composition for an organic antireflective film (“ARC-29”, by NissanChemical Co. Ltd.) was applied onto 12-inch silicon wafers and baked for60 seconds at 205° C. to form a 78 nm thick organic antireflective film.

The above resist compositions were then applied thereon by spin coatingso that the thickness of the resulting film became 85 nm after drying.

The obtained wafers were then pre-baked for 60 sec on a direct hot plateat the temperatures given in the “PB” column in Table 2 to obtain acomposition layer.

Contact hole patterns were then exposed using a mask pattern (holepitch: 100 nm, hole diameter: 70 nm) through stepwise changes inexposure quantity using an ArF excimer laser stepper for immersionlithography (“XT:1900Gi” by ASML Ltd.: NA=1.35, 3/42 annular X—Ypolarization), on the wafers on which the composition layer had thusbeen formed. The ultrapure water was used for medium of immersion.

After the exposure, post-exposure baking was carried out by 60 secondsat the temperatures given in the “PEB” column in Table 2.

Then, puddle development was carried out with 2.38 wt %tetramethylammonium hydroxide aqueous solution for 60 seconds to obtaina resist pattern.

Each resist pattern was produced based on the resist composition usingthe mask pattern (hole pitch: 100 nm, hole diameter: 70 nm) as describedabove. The exposure amount at which a 55 nm-hole diameter was achievedin the pattern was defined as the effective sensitivity.

(Critical Dimension Uniformity (CDU) Evaluation)

The resist patterns were formed by the same method described above usingthe musk of 70 nm of hole diameter with the effective sensitivity. Thehole diameter was measured 24 times per one hole, and an average ofthose was an average hole diameter. The standard deviation was obtainedfrom the average hole diameter based on the population which was 400values of the above average hole diameter within the same wafer.

A “∘ ∘” was given when the standard deviation was less than 1.55 nm,

a “∘” was given when the standard deviation was 1.55 nm or more and lessthan 2.00 nm, and

an “x” was given when the standard deviation was 2.00 nm or more.

A Scanning Electron Microscope (CD SEM Hitachi CG-4000) was used for CDUevaluation.

Table 3 illustrates the results thereof. The parenthetical number meansthe standard deviation (nm).

(Evaluation of Defects)

The above resist compositions were applied on each of the12-inch-silicon wafers by spin coating so that the thickness of theresulting film became 150 nm after drying.

The obtained wafers were then pre-baked for 60 seconds on a direct hotplate at the temperatures given in the “PB” column in Table 2 to obtaina composition layer.

The thus obtained wafers with the produced composition layers wererinsed with water for 60 seconds using a developing apparatus (ACT-12,Tokyo electron Co. Ltd.).

Thereafter, the number of defects was counted using a defect inspectionapparatus (KLA-2360, KLA-Tencor Co. Ltd.)

Table 3 illustrates the results thereof.

TABLE 3 Ex. CDU Defects 1 ∘∘ (1.49) 170 2 ∘ (1.68) 190 3 ∘ (1.85) 230 4∘∘(1.36) 140 5 ∘∘ (1.49) 170 6 ∘ (1.64) 250 7 ∘∘ (1.42) 120 8 ∘ (1.56)160 9 ∘ (1.68) 230 10 ∘∘ (1.44) 130 11 ∘∘ (1.54) 160 12 ∘ (1.68) 220 13∘ (1.89) 400 14 ∘∘ (1.39) 150 15 ∘∘ (1.35) 140 16 ∘∘ (1.42) 180 17 ∘∘(1.39) 190 18 ∘∘(1.31) 120 19 ∘∘ (1.34) 150 Comp. Ex. 1 x (2.28) 720

According to the resist composition of the present invention, it ispossible to produce a resist pattern with excellent CDU and with fewdefects when producing the resist pattern. Therefore, the present resistcomposition can be used for semiconductor microfabrication.

What is claimed is:
 1. A resist composition comprising a resin having astructural unit represented by the formula (I), a resin being insolubleor poorly soluble in alkali aqueous solution, but becoming soluble in analkali aqueous solution by the action of an acid and not including thestructural unit represented by the formula (I), an acid generatorrepresented by the formula (II), and an acid generator represented bythe formula (III),

wherein R¹ represents a hydrogen atom or a methyl group; A¹ represents aC₁ to C₆ alkanediyl group; A¹³ represents a C₁ to C₆ perfluoroalkanediyl group; X¹² represents *—CO—O— or *—O—CO—; * represents a bondto A¹³; A¹⁴ represents a C₁ to C₁₇ aliphatic hydrocarbon group thatoptionally has one or more halogen atoms;

wherein R^(II1) and R^(II2) independently represent a fluorine atom or aC₁ to C₆ perfluoroalkyl group; L^(II1) represents a single bond, a C₁ toC₆ alkanediyl, a C₄ to C₈ divalent alicyclic hydrocarbon group,—(CH₂)_(t)—CO—O—* or —(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—*, one or more —CH₂—contained in the alkanediyl, —(CH₂)_(t)—CO—O—* or—(CH₂)_(t)—CO—O—CH₂—(CH₂)_(u)—* may be replaced by —O—; t represents aninteger of 1 to 12; u represents an integer of 0 to 12; * represents abond to Y^(II1); Y^(II1) represents an optionally substituted C₃ to C₁₈alicyclic hydrocarbon group, and one or more —CH₂— contained in thealicyclic hydrocarbon group may be replaced by —O—, —CO— or —SO₂—;R^(II3), R^(II4), R^(II5), R^(II6) and R^(II7) independently represent ahydrogen atom, a hydroxy group, a C₁ to C₆ alkyl group, a C₁ to C₆alkoxy group, a C₂ to C₇ alkoxycarbonyl group or a C₂ to C₁₂ acyloxygroup, one or more —CH₂— contained in sulfur-containing ring of cationmay be replaced by —O— or —CO—; n represents an integer of 1 to 3; srepresents an integer of 0 to 3; and R^(II8) in each occurrenceindependently represent a C₁ to C₆ alkyl group,

wherein R^(III1) and R^(III2) independently represent a fluorine atom ora C₁ to C₆ perfluoroalkyl group; L^(III1) represents a single bond or aC₁ to C₁₇ divalent saturated hydrocarbon group, one or more hydrogenatom in the saturated hydrocarbon group may be replaced by a fluorineatom or a hydroxy group, and one or more —CH₂— contained in thesaturated hydrocarbon group may be replaced by —O— or —CO—; Y^(III1)represents an optionally substituted C₁ to C₁₈ alkyl group or anoptionally substituted C₃ to C₁₈ alicyclic hydrocarbon group, and one ormore —CH₂— contained in the alkyl group and alicyclic hydrocarbon groupmay be replaced by —O—, —CO— or —SO₂—; and Z⁺ represents an organiccation.
 2. The resist composition according to claim 1, wherein Z⁺ inthe formula (III) is a triaryl sulfonium cation.
 3. The resistcomposition according to claim 1, wherein A¹ in the formula (I) is anethylene group.
 4. The resist composition according to claim 1, whereinX¹² in the formula (I) is *—CO—O—, represents a bond to A¹³.
 5. Theresist composition according to claim 1, wherein A¹⁴ in the formula (I)is a cyclopropylmethyl, cyclopentyl, cyclohexyl, norbornyl or adamantylgroup.
 6. The resist composition according to claim 1, wherein L^(II1)in the formula (II) is a bond or methylene group.
 7. The resistcomposition according to claim 1, which further comprises a solvent. 8.A method for producing a resist pattern comprising steps of (1) applyingthe resist composition of claim 1 onto a substrate; (2) drying theapplied composition to form a composition layer; (3) exposing thecomposition layer; (4) heating the exposed composition layer, and (5)developing the heated composition layer.